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THE
VOYAGE OF H.M.S. CHALLENGER.
ZOOLOGY-VOL. XIII.
REPORT
ON THE
SCIENTIFIC RESULTS
OF THE
VOYAGE OF H.M.S. CHALLENGER
DURING THE YEARS i87 3-7 6
UNDER THE COMMAND OF
Captain GEORGE S. NARES, R.N., F.R.S.
AND THE LATE
Captain FRANK TOURLE THOMSON, R.N.
PREPARED UNDER THE SUPERINTENDENCE OF
THE LATE
Sir C. WYVILLE THOMSON, Knt, F.R.S., &c.
REGIUS PROFESSOR OF NATURAL HISTORY IN THE UNIVERSITY OF EDINBURGH DIRECTOR OF THE CIVILIAN SCIENTIFIC STAFF ON BOARD
AND NOW OF
JOHN MURRAY
ONE OF THE NATURALISTS OF THE EXPEDITION
Zoology— Vol. XIII.
Pui)list)eli bp <0rtJer of !^er ifiajestp's (Sobernment
PRINTED FOR HER MAJESTY'S STATIONERY OFFICE
AND SOLD BY
LONDON :— LONGMANS & CO.; JOHN MURRAY; MACMILLAN & CO.; SIMPKIN, MARSHALL, & CO. TRiJBNER & CO.; E. STANFORD; J. D. POTTER; AND KEGAN PAUL, TRENCH, & CO. EDINBURGH :— ADAM & CHARLES BLACK AND DOUGLAS & FOULIS. DUBLIN :— A. THOM & CO. AND HODGES, FIGGIS, & CO.
1885
Price Fifty Shillings.
PRINTED BY NEILL AND COMPANY, EDINBURGH, FOR HER MAJESTY'S STATIONERY OFFICE.
a y 6 ^
CONTENTS.
I. — Report on the Lamellibranchiata collected by H.M.S. Challenger, during the
The Editor of the Challenger Reports will be greatly obliged to Authors sending him copies of separate papers, or references to works, in which the Challenger discoveries are referred to, or the observations of the Expedition are discussed.
This will greatly facilitate the compilation of a complete Biblio- graphy, and the discussion of the results of the Expedition, in the final Volume of the Series.
Letters and Papers should be addressed—
JOHN MURRA V,
Challenger Office,
22 Queen Street,
EDINBURGH. "S
jt i,fj'v « vyi-'wt/L^ww M| v'f ^» v/ I, i^ *#cLyc. # J.v^i_»-:i: } vic»^ i/vwi/
X yjKjO'j
CONTENTS.
I. — Report on the Lamellibranchiata collected by H.M.S. Challenger, during the
years 1873-1876.
By Edgar A. Smith, F.Z.S., Assistant in the Zoological Department of the
British Museum.
{Received 22nd Januarij 1885 ; Appendices, 11th and 18th June 1885.)
11. — Report on the Gephyrea collected by H.M.S. Challenger, during the years
1873-1876.
By Dr. Emil Selenka, Professor in the University oi Erlangen.
{Received 12th March 1885.)
III. — Report on the Sghizopoda collected by H.M.S. Challenger, during the years
1873-1876.
By Professor G. 0. Sars, of the University of Christiania,
{First Instalment of Manuscript received 27th November 1884 ; the last 7th July 1885.)
ERBA TA.
PAET XXXV.
Page 9, line 3 from foot, for " longicallis " read " longicallus."
Page 14, line 14 from foot, for " Circe australis, Angas " read " Circe angccsi, n. sp."
Page 14, line 1 from foot, for " Corbula truncata " read " Corbula hinicata."
Page 17, line 4 from foot, for " Ccclodon elongata " read " Gcelodon elongatus."
Page 18, line 4 from foot, for " Solen " read " Solecurtus."
Page 20, line 5 from foot, for " Crytodon luzonica " read " Crytodon luzonicus."
Page 20, line 2 from foot, insert " (Chemnitz) " after " Pecten vitreus."
Page 24, line 8 from foot, for " Crytodon fcdklandica " read " Crytodon falhlandicus"
Page 25, line 4 from foot, for " Leda jeffrcysii" read " Leda jeffreysi."
Page 25, line 3 from top, for ^' Mactra {Trigonella) iscd)elliana " read " Mactra {Trigonella) isabellcana."
Page 121, line 19 from foot, for " Bosina" read " Dosinia."
Page 251, line 4 from foot, delete "n. sp."
Page 282, line 5 from foot, for " meridionalis" read " vieridionalc."
EDITOEIAL NOTES.
This volume contains Parts XXXV., XXXVI., and XXXVII. of the
Zoological Series of Reports on the Scientific Results of the Expedition.
Part XXXV. — On the return of the Expedition the Mollusca were placed in the hands of the Rev. R. Boog Watson, F.R.S.E., for description; but after separating out the different species, and labelling the greater part of the known ones, Mr. Watson determined, on account of the large size of the collection, to limit his work to the description of the Scaphopoda and Gasteropoda.
Mr. Edgar A. Smith, F.Z.S., of the British Museum was then requested to undertake the preparation of the Report on the Lamellibranchiata. This he consented to do, and this Part gives the result of his investigations.
Mr. Watson's own Report is now nearly all in type, and will be published in the course of a few months.
Part XXXVI. — The description of the Gephyrea collected by the Expedition was originally undertaken by Professor E. Ray Lankester, F.R.S., but after the publication of Professor Selenka's splendid systematic Monograph on this group. Professor Lankester suggested that it would be much better if an arrangement could be made by which Professor Selenka should take over the examination of the Challenger collection. Professor Selenka com- plied with a request to do so, and this Part gives the result of his labours.
The Report was translated from the German by J. Arthur Thomson, Esq., M.A.
viii THE VOYAGE OF H.M.S. CHALLENGEE.
Part XXXVII. — This Part consists of a Report on the Schizopoda of the Expedition, by the well-known Carcinologist, Professor G. O. Sars, of Christiania. In addition to the present Report. Professor Sars has under- taken another on the Cumacea and Phyllocarida, which will be published in the course of next year.
John Murray.
Challengbk Office, 32 Queen Street, Edinburgh, Isf October 1885.
THE
VOYAGE OF H.M.S. CHALLENGER.
ZOOLOGY.
REPORT on the Lamellibrancuiata collected by H.M.S. Challenger during the Years 1873-76. By Edgar A. Smith, F.Z.S., Assistant in the Zoological Department of the British Museum.
INTRODUCTION.
The following Report upon the Lamellibranchiata obtained during the Challenger Expedition consists almost exclusively of a list of the vaiious species compiised in the collection, with such remarks connected with each as were thought to be of sufficient interest for publication, and of the descriptions of the numerous forms which apparently are new to science. The time at my disposal for the preparation of the work ha\'ing been rather limited, the revision of several of the genera, which in the course of studying some of the species has appeared desirable, has had to be abandoned. Only in a few instances has an account of the soft parts preserved in spirit been given, as these are to be placed in other hands for examination and anatomical description.
Before the collection was handed over to me it had already to a great extent been identified by the Rev. R. Boog Watson, who is reporting on the Scaphopoda and Gasteropoda of the Expedition, and it is with much pleasure that I bear testimony to the very great assistance I have derived from his labours.
In the first place, I escaped the great trouble of sorting the numerous species into separate boxes and bottles, and of writing the localities, depths, &c., upon them. This, however, is but a slight advantage in comparison with that of having the identifications of one whose powers of perception are second to those of no other conchologist of my acquaintance, and whose carefulness and thoroughness must have been recognised by
(ZOOU CHALL. EXP. — PART XXXV. — 1885.) Mm 1
2 THE VOYAGE OF H.M.S. CHALLENGER.
all fellow-workers, whom, in the course of the preparation of his Report, he may have consulted. This is also a fitting place to record the assistance I have derived from the late Dr. Gwyu Jcfi'roy's writings on the deep-sea fauna of the North Atlantic, and to acknowledge his courtesy in kindly giving his opinion upon certain difficult and doubtful questions. To my friend W. H. Dull, of the Smithsonian Institution, I am under similar obligations.
The name Pelecypoda given to this section of MoUusca by Goldfuss ' ought, I think, to be used in preference to that of Lamellibranchiata. Not only has it priority, but, as pointed out by Stoliczka, it is also more in uniformity with the nomenclature of the other classes of Mollusca, the Cephalopoda, Pteropoda, Gasteropoda, &c., and points to the modification of one of the most important organs — that of locomotion — of the animals.
This class was designated Lamellibranches by Blainville ^ as early as the year 1816, four years before the publication of Pelecypoda by Goldfuss, but was not characterised, and the term Lamellibranchiata, accomj^auied by a description of the class, did not appear until the year 1824, in Blainville's article on Mollusca in the Diet. d. Sci. Nat., vol. xxxii. p. 306. It will therefore be seen that Pelecypoda, although published somewhat later than Lamellibi'anches, was in reality the first to be characterised. I should also here notice that Blainville imposed the name Tetrabranches upon the bivalves^ two years before the invention of Lamellibranches, but, in that instance also, unaccompanied by any description. The class-names " Acephala" of Cuvier and " Conchifera" of Lamarck were published a year or two prior to the appearance of Goldfuss's work, but, as they include groups which are regarded in modern science as distinct classes, their adoption is not advisable, seeing that Pelecypoda applies only to true bivalve MoUuscs as now under- stood. The name Lamellibranchiata is used in the present Eeport as it appears in the several works published by Sir Wyville Thomson, Professor H. N. Moseley, and others in connection with the voyage of the Challenger, also in the Narrative of the Cruise, and because it had already been wTitten on some of the plates before this subject of nomen- clature had been studied.
In describing the new species I have deemed it advisable to give Latin diagnoses, as practical experience has proved to me the advantage of such descriptions, and the custom is adopted by continental writers almost without exception. Through long use the Latin terminology has acquired a settled signification, and is generally understood, which is not the case in resj)ect of other languages, and the time has not yet arrived that any one particular modern language is universally so thoroughly known that its adoption as the language of science can be determined upon.
1 Handbuch der Zoologie, 1820, vol. i. p. 599.
2 Bull. Soc. Fhilom. Paris, 1816, p. 122 ; and Journ. de Physique, 1816, vol. Ixxxiii. p. 255. s Bull. Soc. Philom. Paris, 1814, p. 179.
IIEPORT ON THE LAMELLIBRANCHIATA.
GENERAL REMARKS ON THE COLLECTION.
I have already given a brief notice of the collection, which will be found incorporated in tlie Narrative of the Voyage,^ and the views there expressed require little modification.
The collection, as a whole, is in some respects disappointing. Considering the character of the Expedition, the appliances with which it was furnished, the able staff of scientific men on board, and the number of Stations dredged, it certainly does seem surprising that only about five hundred species" should have been obtained. This, however, may not be three-fourths of the number of forms which actually passed into the dredge or trawl, for doubtless a certain proportion, perhaps a large percentage, of the secured material, and possibly some of the most valuable, must have found its way through the meshes of the network during the process of hauling in, especially from very great depths. Another disappointing feature of the collection is that the species are represented in tke majority of instances by very few specimens, there being of many of them but single or a few odd valves, some of which arc in a bad state of preservation. The greater part of the collection consists of species from comparatively shallow water, Torres Strait, the Arafura Sea, Port Jackson, Bass Strait, Fiji, Kerguelen and Marion Islands, supplying a large proportion.
As might be expected, some of the forms are of particular interest when great depths have been reached, but it is a remarkable fact that only one distinctly new generic type was discovered.^
The greatest depth at which Lamellibranchs were obtained was 2900 fathoms (Station 244, in Mid North Pacific). Of the two species from this enormous depth one is a small fragUe shell which I have named Callocardia i^acijica; I should here observe, and it is a most interesting fact, that a second species [Callocardia atlantica) was dredged in 1000 fathoms off the Azores, which is all but identical with that from the Pacific. A third species of this genus [Callocardia adamsii) was also obtained in very deep water in the Atlantic to the south-west of Sierra Leone. The second species, from Station 244, belongs to Ahra, which I regard as a subgenus of Semele.
The other Stations, ranging from depths of 1000 to 2650 fathoms, at which Lamelli- branchs were obtained are Nos. 45, 47, 56, 70, 71, 73, 78, 85, 98, 104, 106, 113, 133, 135E, 137, 146, 157, 158, 184, 198, 205, 216, 218, 244, 246, 271, 281, 300, 302, 317, 323, 325, and 348. I have quoted these numbers so that reference can be made to the
1 Narr. Cliall. Exp., vol. i. pp. 624-02B, 1S85.
2 This does not include a small number of species represented only by odd valves, which are beyond identification owing to their younj; state or bad conditidn.
' A still more remarkable absence of generic novelties occurred in the case of the Brachiopoda, not a single ntw form having been described by Mr. Davidson.
4 THE VOYAGE OF H.M.S. CHALLENGER.
List of Stations given further on, by tliose interested to know the actual species found in such deep water. I here merely make a few observations respecting the different genera there met with. At the above thirty-three Stations only twenty-three different genera were found, although the majority of these occurred in more than one place. The genera Amussium and Area were met with at seven of the Stations ; Necera at five ; Lima and Callocardia at four ; Malletia, Limopsis, Cryptodon, Ahra, Lyonsiella, and Verticordia &tihxe&; Leda, Nucula, Pecten, Silenia, and Sarepta at two; and Modiolaria, Dacrydium, Pectuncidus, Venus, Myrina, and Glomus at one only.
Some of the species occurred in more than one locality, showing at times a very remarkable geographical distribution.
The following are some of the principal instances : —
Silenia sarsii,
Saxieam arctica, .
Semele [Abra) profundorum,
Petricola lapieida, .
Venus (Chamelcea) mesodesma,
Cardium siieziense, Verticordia deshayesiana,
Kellia suborhieidaris, . Astarte magellanica, Cardita calyculata,
Nuculina ovalis, .
Sarepta ahyssicola,
Limopsis pelagica,
Area imbricata,
Area {Barbatia) pteroessa,
About 1100 miles south-west of Australia, in 1950
fathoms ; also off the mouth of the Eio de la Plata, in
2650 fathoms. Cosmopolitan, 0 to 500 fathoms. Near the Canary Islands, in 1125 fathoms, and Mid
North Pacific, in 2900 fathoms. North Australia, in 7 fathoms ; a well-known West
Indian form. New Zealand, on the beach, and off Tristan da Cunha, in
1000 fathoms. A Red Sea species ; from Fiji, in 12 fathoms. Off Pernambuco, in 350 fathoms, and near Cape York, in
155 fathoms. A British species ; from Kerguelen Island, in 28 fathoms. A Strait of Magellan species ; from ]\Iarion Island. Off Tenerife, in 70 fathoms, and in Bass Strait, in 38 to
40 fathoms. A fossil of the Suffolk Crag ; from the Cape of Good
Hope, in 15 to 20 fathoms. Mid North Pacific, in 2050 fathoms, and Mid South
Pacific, in 2385 fathoms. Mid Atlantic, in 1850 fathoms, and off Japan, in 345
fathoms. A West Indian species, from near Cape York, in 25 fathoms. Mid North Pacific, in 2050 fathoms; west of the Azores,
in 1000 and 1675 fathoms; and the West Indies, in
390 fathoms.
REPORT ON THE LAMELLIBRANCHIATA.
Area {Barbatia) corpulenta,
Mytilus edulis, Mytilus magellanicus
Modiolaria cuneata, Lima squamosa,
Lima lata, .
Lima multicostata,
Lima goliaih,
Lima loscomhii,
Pecten vitreus,
North-East Australia, iii 1 400 fathoms ; south of
Amboyna, in 200 to 3G0 fathoms; Mid Pacific, in
2425 fathoms; and near the Lshind of Juan Fernandez,
in 1375 fathoms. Cosmopolitan. Falkland Islands, Kerguelen Island, and Fiji, all in
shallow water. Port Jackson and the Cape of Good Hope, shallow water. Tenerife, in 70 fathoms, and the Philippine Islands, in
10 fathoms. St. Paul's Eocks, Atlantic, in 104 fathoms, and
Philippine Islands, in 82 fathoms. Port Jackson, in 2 to 1 8 fathoms ; Tongatabu, in 1 8
fathoms ; and off Bermuda, in 1075 fathoms. South Japan, in 775 fathoms, and South Patagonia, in
245 fathoms. A British species ; from the Azores, in 450 fathoms, and
Tristan da Cunha, in 100 to 150 fathoms. West coast of Patagonia, in 140 to 400 fathoms ; South
Japan, in 345 fathoms ; and Philippine Islands, in
100 to 700 fathoms.
A perusal of the above will show that some of the species were obtained not only at widely distant localities, but also at very different depths. Venus mesodesma (a shore species) was dredged in 1000 fathoms. Area pteroessa in 390 and 2050 fathoms, Lima midticostata in 2 and 1075 fathoms, Pecten vitreus in 140 and 700 fathoms, Necera ohesa in 40 and 1000 fathoms, Ervilia castanea in 70 and 1000 fathoms, and Dacrydium vitreum and Pecten pldlippii, both of which have been obtained in less than 40 fathoms, were hauled up respectively from 1000 and 450 fathoms. I might multiply examples of the different ranges in depth at which various species have been obtained by the Challenger and other expeditions, but those which I have cited are sufficient to show that the same species is equally well adapted for living in deep or shallow water, and, as far as I have noticed, the shells appear to be very little aflfected by the difierenee of the depth or the nature of the bottom.^ As a rule, very deep-water "benthal" species certainly have a tendency to be without colour, and of thin structure, no doubt resulting from the absence of light, the difficulty of secreting lime, the scarcity of food, and other unfavourable conditions of existence.
1 Mr. Davidson has also mentioaed instances of Bracliiopods " capable of existing at a great variety of depth," one species (Terebratuki vitrea) ranging from 5 to 1456 fathoms. Zool. C'liall. Kxp., part i. p. 6, 1880.
6 THE VOYAGE OF H.M.S. CHALLENGER.
But then most of them belong to genera the species of which from shallow depths are comparatively thin, and more or less devoid of colour. For instance, I may mention Necera, Lima, Cr>J2^tod'on, Ahra, Lyonsiella, Verticordia, SarejJta, and DacrijdiuiH. The deep-water species of such genera as have a decided epidermis (as Mallctia, Limopsls, Leda, Nucula, and Area) still retain it, with but little if any modification.
From a study of the Challenger collection it would therefore appear that the Lamellibraneh fauna of the deepest parts of the Atlantic and Pacific Oceans is not of a very extraordinary, and certainly not of a special, character. The species are apparently few in number in comparison with those of shallow water, and new and peculiar generic forms which we naturally expected would have been discovered are of even still i-arer occurrence.
In support of the theory that Molluscan life is comparatively scarce at great depths, I may give the following particulars. Species were obtained on forty-three occasions at depths of less than 100 fathoms, at twenty-four Stations at depths between 100 and 500 fathoms, at ten only in 500 to 1000 fathoms, and at thirty-three in 1000 to 2900 fathoms. At the diflerent Stations of the first range, 384 ^ species were collected, 148 at those of the second, 24 at those of the third, and 70 at those of the fourth, so that it will be seen that the average number of species per Station at the different ranges is as follows : —
At depths of 0 to 100 fathoms 9 species. „ 100 to 500 „ 6-16 ,
500 to 1000 „ 2-4 „ 1000 to 2900 „ 2-12 „
These figures therefore clearly show that the deeper the Challenger dredged the fewer were the species obtained.
Mr. Davidson, in his Eeport on the Brachiopoda of the Expedition, has arrived at ii similar conclusion, for he observes that they " are more numerous both in species and individuals at depths of less than 500 fathoms," and that it is "apparent that Brachiopoda do not, as far as our experience goes, generally abound in depths exceeding 500 or 600 fathoms ; for out of one hundred and twenty -five dredgings in depths of from 1 to 600 fathoms, Brachiopoda were brought uji twenty-two or twenty -three times, while in depths varying from 600 to 2900 fathoms they were obtained about sixteen times."
1 It should be remarkeil that a good many of the species were found at more than one Station, hence the total number of species here given from those four ranges greatly exceeds the actual number of different species in the collection.
GEOGEAPHICAL DISTRIBUTION.
The following is a complete list of the Stations at which bivalves were obtained. The exact latitude and longitude, the depth and the nature of the bottom, will be given in this place, but not under the "habitat" of each species, so that needless repetition will be avoided. Only the number of the Station is quoted in the body of the work, but the geographical position is given to save the reader the inconvenience of constantly referring back to the subjoined list.
Under each Station are also given the names of the species there obtained, which will be of use to those interested in the study of special faunas.
The order of the Stations follows the course of the voyage, and such localities as have no Station number assigned to them follow those numbered Stations to which they are most closely situated.
Station II.— January 13, 1873 ; lat. 38° 10' N., long. 9° 14' W. ; depth, 470 fathoms ; bottom, green mud (off the west coast of Portugal).
Limopsis minuta, Philippi. | Pecten sulcatus, var.
Leila rectidorsata, Seguenza (?).
Station VIII.— February 12, 1873; lat. 28° 3' 15" N., long. 17° 27' ^Y. ; depth, 620 fathoms ; bottom, volcanic mud (a little south of the Canary Islands).
Lyonsia formosa, Jeffreys. JSfecBva teres, Jeffreys. Montacuta pura, n. sp.
Cryptodqn croulinensis, Jeffreys. Limopsis minuta, Philippi. Leda messanensis, Seguenza.
Station 23.— March 15, 1873 ; lat. 18° 24' K, long. 63° 28' W. ; depth, 450 fathoms; bottom, Pteropod ooze (off Sombrero Island, West Indies).
Necera claviculata, Dall.
Necera sp. Cryptodon sp.
Limopsis aurita, Brocchi. Lima {Limatula) confusa, n. sp. Lima [Limatula) laminifera, n. sp.
Station. — St. Thomas, West Indies ; depth not stated.
Amussium cancellatum, n. sp.
THE VOYAGE OF H.M.S. CHALLENGER.
Station 24.— March 25, 1873 ; lat. 18° 38' 30" N., long. 65° 5' 30" W. ; depth, 390 fathoms; bottom, Pteropod ooze (off Culebra Island, West Indies).
Verticordia ivoodii, n. sp. Necera consociata, n. sp. NecBra sp.
Montacuta occidentalis, n. sp. Cryptodon incrassatus, var. CrassatcUa parva, C. B. Adams. Idas dalli, n. sp. Dacrydium occidentale , n. sp. Area (Barbatia) pteroessa, n. sp. Area [ScaiJharea?) incequiseidpta ,
n. sp. Area (Scapharea ?) culebrensis,
n. sp. Limopsis minuta, Phili^ipi. Nucida eulehrensis, n. sp. Leda deeipiens, u. sp.
Leda inaudax, n. sp.
Leda hebes, n. sp.
Leda despeeta, n. sp.
Malletia veneriformis, n. sp.
Malletia euneata, n. sp.
Glomus ji'ffreysii, n. sp.
Glomus simp>h'x, n. sp.
Glomus incequdatcndis, n. sp.
Glomus S]).
Peeten culebrensis, n. sp.
Peeten sp.
Peeten sp.
Amussium squamigerum, u. sp.
Amussium ohliquum, n. sp.
Amussium cancellatum, n. sp.
Lima (Limatula) laminifera, n. sp.
Station. — North Atlantic, deep water (probably off Bermuda).
Mo7itaeuta cylindracea, n. sp.
Lucina (Codah'a) tigrina, Linne.
Station 33.— April 4, 1873; lat. 32° 21' 30" N., long. 64° 35' 55" W. ; depth, 435 fathoms ; bottom, coral mud (off Bermuda).
Ciree bermudensis, u. sp.
Ervilia subcancellata, n. s Verticordia ornata, var. Corbula philippii, n. sp. Necera consociata, n. sp. Necera elavictdata, Dall. Necera congenita, n. sp.
Station. — Bermuda, depth,-
Lithodomus antillarum, Philippi
Necera curta, Jefireys. Lucina [CodaJcia) pecfe«, Lamarck. Cryptodon barbata, Eeeve (?). Malletia veneriformis, n. sp. Amussium dalli, n. sp. Amussium squamigerum, n. sp. Amussium cancellatum, n. sp.
(?), probably shallow water.
Lithodomus appendieidatus, Philippi.
Station 36.— April 22, 1873; lat. 32° 7' 25" N. bottom, coral (off Bermuda). Area noce, Linne. Area {Aear) domingensis, Lamarck.
long. 65° 4' W.; depth, 30 fathoms ;
Avicula [Meleagnna) squamulosa, Lamarck.
Lima (Mantellum) Mans, Gmelin.
REPORT ON THE LAMELLIBRANCHIATA.
9
Station 45.— May 3, 1873; lat. 88° 34' N., long. 72° 10' W.; depth, 1240 fatlioms; bottom, blue mud (off the east coast of the United States).
Malletia ohtusa, Sars.
Station 47.— May 7, 1873; lat. 41° 14' N., long. G5° 45' W.; depth, 1340 fathoms; bottom, blue mud (south of Nova Scotia).
Malletia ohtusa, Sars.
Station 56.— May 29, 1873; lat. 32° 8' 45" N., long. 64" 59' 35" W.; depth, 1075 fathoms; bottom, coral mud (oflF Bermuda).
Limopsis awita, Brocchi. | Amussium cancellatum, n. sp.
Lima multicostata, Sowerby.
Station 70.— June 26, 1873; lat. 38° 25' N., long. 35° 50' W.; depth, 1675 fathoms; bottom, Globigerina ooze (Mid North Atlantic, west of the Azores).
Verticordia tornata, Jeffreys. | Modiolaria semig7'anata, Reeve.
Leda excisa, Philippi.
Station 71.— June 27, 1873; lat. 38° 18' N., long. 34° 48' W.; depth, 1675 fathoms; bottom, Globigerina ooze (a little east of Station 70).
Area [Barbatia) pteroessa, n. sp.
Station 73.— June 30, 1873; at. 38° 30' N., long. 31° 14' W.; depth, 1000 fathoms; bottom, Pteropod ooze (a little west of the Azores).
Semele (Ahxi) profundorinn, n. sp. Callocardia (?) atlantica, n. sp. Necera circinata, Jeffreys. NecBra wollastonii, n. sp.
Dacrydium vitreum, MciUer. Aiva (Barbatia) pteroessa, n. sp. Limopsis aurita, Brocchi. Amussium lueidum, Jeffreys.
Station 75.— July 2, 1873; lat. 38° 38' N., long. 28° 28' 30" W.; depth, 450 fathoms; bottom, volcanic mud (off the Azores).
Cii'ce minima, Montagu.
Venus ( Ventricola) casina,
Linne. Venus ( Ventricola) effossa, Bivona. Venus (Chione) ovata. Pennant.
Tellina ( ?) donacina, Linne.
Semele [Abra) longicalUs, Scacchi. Ervilia castanea, Montagu. Chama gryphoides, Linne.
(ZOOL. CHALL. ESP. PART XXXV. 1885.)
Cardium {Acanthocardium) papil- losum, Poli.
Cardium (Paj^yridea) transver- sale, Deshayes.
Saxicava arctica, Linne.
Necera curta, Jeffreys.
Montacuta pur-a, n. sp.
Cryptodon flexuosus, Montagu.
Area tetragona, Poli.
Mm 2
10
THE VOYAGE OF H.M.S. CHALLENGER.
Station 75 — continued.
Limopsis minuta, Philippi. Leda messanensis, Segueuza. Pccten pusio, Linue. Pecten phdippii, Edcluz.
Station 78.— July 10, 1873; lat. 37° 26' N bottom, volcanic mud (oflf the Azores).
Callocardia (?) atlantica, n. sp. Necera obesa, Loven. Necera azorica, n. sji. Cryptodon croidinensis, Jeffreys. Dacrydium vitreum, MoUer. Nucula reticidata, Jeffreys.
Station. — Off Tenerife, Canary Islands; depth,
Cytherea {Callista) chione, Linne. Circe minima, Montagu. Venus [Ventricola) casina, Linne. Ventis (Ventricola) effossa, Bivona. Venerupis irus, Linne. Psammobia costulata, Turton. Ervilia castanea, Montagu. Cliama gryphoides, Linne. Cardium (Acanthocardium) papil- losum, Poli.
Pecten testce, Bivona. Pecten gihhus, Linne. Lima {Mantellum) Sowerby.
loscomhii.
long. 25° 13' W.; dejith, 1000 fathoms;
Leda confinis, n. sp. Leda Jeffrey si, Hidalgo. Amussium propiiiquum, n. sp. Amussium litcidiim, Jeffreys. Lima (Limattda) subovata, Jeffreys. Lima [Limatula] confusa, n. sp.
70 fathoms.
Cardium [Papyridea) transver- sal e, Deshayes. Gastroch(Ena duhia. Pennant. Diplodonta apicalis, Philippi. Astarte macandreivi, Smith. Cardita calycidata, Linne. Pectunculus stellatus, Bruguiere. Pecten pusio, Linne. Pecten corallinoides, d'Orbigny. Lima squamosa, Linne.
Station 85.— July 19, 1873; lat. 28° 42' N., long. 18° 6' W.; depth, 1125 fathoms; bottom, volcanic mud (west of the Canary Islands).
Seinele (Abra) profimdorum, n. sp. | Verticordia quadrata, n. sp.
Neasra circinata, Jeffreys.
Station. — St. Vincent, Cape Verde Islands; depth, 7 to 20 fathoms.
Venus (Anaitis) paphia, var. Psammobia intermedia, Deshayes. Cardium. {Lcevicardium) norvegi- cum, var.
Pecten corallinoides, d'Orliigny,
GastrochcBua dubia, Pennant. Lucina columbella, Lamarck. Area (Acar) domingensis, Lamarck. Pectunculus formosus, Eeeve.
REPORT ON THE LAMELLIBRANCHIATA. ' 11
Station 98.— August 14, 1873; lat. 9° 21' N., long. 18' 28' W.; depth, 1750 fathoms; bottom, Globigerina ooze (west of Sierra Leone, West Africa).
Semele (Abra) 2)rofundorum, n. sp. | Necerajilocarinata, n. sp.
Station 104.— August 23, 1873 ; lat. 2° 25' N., long. 20° 1' W.; depth, 2500 fathoms ; bottom, Globigerina ooze (Mid Atlantic, between Sierra Leone and North Brazil).
Lima (Limatula) sp.
Station 106.— August 25, 1873 ; lat. 1° 47' N., long. 24° 26' W. ; depth, 1850 fathoms ; bottom, Globigerina ooze (somewhat west of Station 104).
Verticordia tornata, Jeffreys. | Lyonsiella jeffi-eysii, n. sp.
Limopsis pelagica, n. sp.
Station 109.— August 28, 1873; lat. 0° 55' 38" N., long. 29° 22'35"W.; depth, 104 fathoms ; bottom, hard ground (off St. Paul's Rocks, Mid Atlantic).
Lima lata, n. sp.
Station 113.— September 1, 1873; lat. 3° 40' 45" S., long. 32° 22' W.; depth, 1010 fathoms ; bottom, hard ground (off Fernando Noronha, north-east of Brazil).
Pectuncidus iJectinatus, Gmelin.
Station 11 3a.— September 1, 1873; lat. 3° 47' S. ; long. 32° 24' 30" W. ; depth, 25 fathoms ; bottom, volcanic sand and gravel (anchorage of Fernando Noronha).
Ervilia subcancellata, n. sp. Cardium (Fragum) medium, Linne. Lucina [Codahia) p>ecten, Lamarck.
Mytilus exustiis (Lamk.), Reeve. A7'ca imhricata, Bruguiere. Pecten noronliensis, n. sp.
Station 120.— September 9, 1873; lat. 8° 37' S., long. 34° 28' W.; depth, 675 fathoms; bottom, red mud (off Pernambuco, Brazil).
Ervilia subcancellata, n. sp. Leda solidula, n. sp.
Nucida pernambucensis, n. sp. ' Amussium lucidum, Jeffreys.
Lima {Limatula) confusa, n. sp.
Station 122.— September 10, 1873; lat. 9° 5' S.,long. 34°50' W.; depth, 350 fathoms; bottom, red mud (a little south of Station 120).
Semele obliqua, jun.
Semele (Abra) braziliensis, n. sp.
Verticordia deshayesiana, Fischer.
Verticordia woodii, n. sp. Mytihis exiistus (Lamk.), Reeve. Leda semen, n. sp.
Anomia ephipjiium., var.
12 THE VOYAGE OF H.M.S. CHALLENGER.
Station. — Bahia, Brazil ; depth, 7 to 20 fathoms.
Cardium [Papyridea) hullatum (Linne f), Chemnitz.
Station 133.— October 11, 1873; lat. 35° 41' S., long. 20° 55' W.; depth, 1900 fathoms; bottom, Globigerina ooze (Mid South Atlantic).
Lyonsiella grandis, n. sp. | Cryptodon moselcyi, n. sp.
Station. — Nightingale Island, Tristan da Cunha ; depth, 100 to 150 fathoms.
Venus philomela, n. sp. Saxicava arctica, Linne. Diplodonta sp. CarditeUa exulata, n. sp.
Pecten limatida, var.
Lima (Mantelluin) loscomhii,
Sowerby. Lima [Limatula) sp.
Anomia ephippiwn, var.
Station 135e.— October 18, 1873; lat. 37° 21' S., long. 12° 22' 30" W. ; depth, 1000 fathoms ; bottom, hard ground, shells, gravel (off Tristan da Cunha).
Venus {Chamelcea) mesodesma, Quoy and Gaimard.
Station 137.— October 23, 1873 ; lat. 35° 59' S., long. 1° 34' E.; depth, 2550 fathoms ; bottom, red clay (Mid South Atlantic, between Tristan da Cunha and Cape of Good Hope).
Malletia pallida, n. sp.
Station. — Off the Cape of Good Hope ; depth, 15 to 20 fathoms.
Tellina (Angulus) natalensis,
Krauss. Cardium (Papyridea) semisulca-
tum, Gray.
Cardita (Thecalia) concamerata,
Chemnitz. CarditeUa capensis, n. sp. Nuculina ovalis, Searles Wood.
Station 141.— December 17, 1873 ; lat. 34° 41' S.,long. 18° 36' E.; depth, 98 fathoms; bottom, green sand (off the Cape of Good Hope).
Saxicava arctica, Linne. I Pecten limatula, var.
Station 142.— December 18, 1873 ; lat. 35° 4' S., long. 18° 37' E.; depth, 150 fathoms ; bottom, green sand (off the Cape of Good Hope).
Saxicava arctica, Linne. | Nccera capcnsis, n. sp.
REPORT ON THE LAMELLIBRANCHIATA.
13
Station. — Off Marion and Prince Edward Islands in the Southern Ocean, south-east of the Cape of Good Hope ; depth, 50 to 300 fathoms.
Davila umhonata, n. sp. Thracia meridionalis, n. sp. Saxicava arctica, Linnd. NecBva fragilissivia, n. sp. Cryptodon marionensis, u. sp, Astarte magellanica, n. sp. Mytilus meridionalis, n. sp.
CreneUa marionensis, n. sp.
Modlolarca trajiezina, Lamarck,
Dacrydium meridionals, n. sp,
Limopsis marionensis, u. sp.
Pecten distinctus, n. sp.
Pecten avicidoides, n. sp.
Lima {Limatula) pygmcea, Philippi.
Station 146.— December 29, 1873; lat. 46° 46' S., long. 45' 31' E. ; depth, 1375 fathoms ; bottom, Globigerina ooze (Mid Southern Ocean).
Pecten pudicus, u. sp. | Amussium meridionale, n. sp.
Station. — Kerguelen Island; depth, shore to 120 fathoms; bottom, volcanic mud.
Davila (?) umhonata, n. sp. Anatina elliptica, jun. Tliracia meridionalis, n. sp. Necera kerguelensis, n. sp. Kellia suhorhicidaris, Montagu. Kellia cardiformis, n. sp. Kellia nuculina. Martens, Cardita astartoides, Martens,
Mytilus kerguelensis, n. sp. Mytilus magella n icus, Chemnitz. Modiolarca trapezina, Lamarck. Modlolarca kerguelensis, n. sp, Yoldia isonota, Martens. Yoldia subcequilctteralis, Smith. Malletia gigantea, Smith. Pecten clathratus, Martens,
Lima [Limatula) pygmcea, Philippi.
Station 150.— February 2, 1874 ; lat. 52° 4' S., long. 71° 22' E. ; depth, 150 fathoms; bottom, coarse gravel (south-east of Kerguelen Island).
Saxicava arctica, Linne. Cardita astartoides, Martens,
Mytilus meridionalis, n. sp. Limoj)sis straminea, n. sp.
Station 157.— March 3, 1874; lat. 53° 55' S., long. 108° 35' E.; depth, 1950 fathoms; bottom. Diatom ooze (Mid Ocean, south-west of Australia).
Lyonsiella papyracea, n. sp. | Silenia sarsii, n. sp.
Necera meridionalis, n. sp.
Station 158,— March 7, 1874; lat. 50° 1' S., long. 123° 4'E.; depth, 1800 fathoms; bottom, Globigerina ooze (somewhat north-east of preceding Station).
Amussium meridioncde, n, sp.
14
THE VOYA.GE OF H.M.S. CHALLENGEK.
Station 161.— April 1, 1874; lat. 38° 22' 30" S., long. 144' 36' 30" E.; depth, 33 fathoms ; bottom, sand (oif the entrance to Port Philip, South Australia).
Cardmm (Bucardium) 'pulchellum, Gray.
Leda crassa, Hinds. Leda ensicula, Angas.
Station 162.— April 2, 1874 ; lat. 39° 10' 30" S., long. 146° 37' E.; depth, 38 fathoms ; bottom, sand and shells (off East Moncoeur Island, Bass Strait).
Cytherea (Callista) rutila, Sowerby. Venus (CJiione) striatissima,
Sowerby. Thracia ivatsoni, n. sp. Thracia myodoroides, u. sp. Myochama anomioides, Stutchbury. Cardium [Bucardium) pidchellum,
Gray. Kellia rotunda, var. Cardita calyculata, var. Cardita dilecta, n. sp. Cardita beddomei, n. sp.
Cardita himacidata, Deshayes. Crassatella aurora, A. Adams and
Angas. Trigonia margaritacea, Lamarck. Area (Barhatia) radtda, A. Adams. Pectuncidus beddomei, n. sp. Limopsis hassi, n. sp. Pinna tasmanica, Ten. Woods (?). Peeten asperrimus, Lamarck. Pecten undidatus, Sowerby. Lima (Limatula) bullata, Born.
Station. — Port Jackson, Sydney ; depth, shallow water, 2 to 35 fathoms.
Dosinia circinaria, Deshayes. Cytherea (CalUsta) disrwpta, Sowerby.
Circe scri])ta, Linne.
Circe australis, Angas.
Venus (Chione) calophylla^ Philippi.
Vemis [Chione) jacksonii, n. sp.
Venus [Chione) striatissima,
Sowerby. Venus [Leukoma) australis,
Sowerby. Tapes [Paratapes) textrix, Chemnitz. Tapes [Amygdala) fabagclla,
Deshayes. Psammobia zonalis, Lamarck. Saxicava arctica, Linne. Solen sloanii. Gray. Corbula truncata. Hinds.
Neaira bi-azieri, n. sp.
Kellia rotunda, var.
Kellia adamsi, Angas.
Montacuta angasi, n. sp.
Lucina ramsayi, n. sp.
Lucina [Loripes ?) jacksonensis,n. sp.
Diplodonta sp.
Cardita sp.
Psammobia modesta, Deshayes.
Tellina [ ?) semitorta, Sowerby.
Donax nitidus, Deshayes. Mactra [Trigonella) imsilla,
A. Adams. Mactra [Trig07iella) jachsonensis,
n. sp. Mactra [Mactrinula) depressa,
Eeeve. Ervilia hisctdpta, Gould.
REPORT ON THE LAMELLIBRANCHIATA.
15
Station. — Port Jackson, Sydney — continued. Chama splnosa, Broderip. Thracia modestn, Angas. Myodora ixindoriformis, Stutcli-
bury. Myodora hrcvis, Sowerby. Myodora crassa, Stutchbiuy. Myodora australis, Reeve. Myodora angustata, Angas. Myochama anomioides, Stutclibnry. Cardium (Bucardium) tenuicos-
tatum, Lamarck. Cardium (Bucardium) pidchellum,
Gray. Cardita excavata, Deshayes. Carditella angasi, n. sp. Mytilus hirsutus, Lamarck.
ModioJa glaberrima, Dunker. ModioJaria laniger, Dunker. Modiolaria cumingiana, Dunker. Modiolaria vancosa, Gould. Modiolaria cuneata, Gould. Trigonia lamarckii, Gray. Area (Barhatia) fasciata, Eeeve. Aixa {Scapharca) gubernacidum,
Reeve. Pectuncidus holosericus, Reeve. Pectuncidus s(na<MZaW.9,Lamarck(?). Limopsis hrazieri, Angas. Pecten [Janira) fumatus, Eeeve. Lima multicostata, Sowerby. Lima angulata, Sowerby. Lima (Limatida) hullata, Born.
Station 164.— June 12, 1874 ; lat. 34° 8' S., long. 152° E.; depth, 950 fathoms; bottom, green mud (off the coast of New Soiith Wales).
Leda inojiinata, n. sp. | Leda ramsayi, n. sp.
Station 164b.— June 13, 1874; lat. 34° 13' S., long. 151° 38' E.; depth, 410 fathoms; bottom, green mud (off the coast of New South Wales).
Necera angasi, n. sp.
Station 167a.— June 27, 1874; lat. 41° 4' S., long. 174° 19' E.; depth, 10 fathoms; bottom, mud (Queen Charlotte Sound, New Zealand).
Dosinia lamhata, Gould. Cytherca (Callista) multistriata,
Sowerby. Psammohia lineolata, Gray.
Station. ^D'Urville Island, New Zealand ; shore. Venus ( Chamelcea) mesodesma, Quoy and Gaimard.
Tellina {TellineUa) charlottce^
n. sp. Tellina [TellineUa) huttoni, n. sp. Nuctda nitidida, A. Adams.
Tapes (Amygdala) intermedia, Quoy and Gaimard.
Mytilus edulis, Linne.
Station 169.— July 10, 1874; lat. 37° 34' S., long. 179° 22' E.; depth, 700 fathoms; bottom, blue mud (off" the north-east coast of New Zealand).
Limopsis lata, n. sp.
16
THE VOYAGE OF H.M.S. CHALLENGER.
Station 171.— July 15, 1874; lat. 28° 33' S., long. 177° 50' W.; depth, GOO fathoms; bottom, hard ground (north of the Kermadec Islands),
Pecten kermadecensis, n. sp.
Station 172.— July 22, 1874; lat. 20° 58' S., long. 175° 9' W.; depth, 18 fathoms; bottom, coral mud (off Tongatabu).
Venus [Antigona) puerpera, var.
Circe arnica, n. sp.
Psammohia pulcherrima, Des-
hayes. Psammohia castrcnsis, Spengler. TelUna (Tdlinella) verrucosa,
Hanley.
Chama brassica, Reeve. Cardium (Fragum) fornicatum,
Sowerby. Corhula modesta. Hinds. Lucina (CodaJcia) interrupta,
Lamarck. Pecten amicus, n. sp.
Lima midticostata, Sowerby.
Station. — Fiji Islands ; depth, 0 to 12 fathoms.
Cytherea (Dione) philipjoinarum,
Hanley. Circe sulcata, Gray. Circe gordoni, n. sp. Venus {Chione) marica, Linnd. Venus (Chione) levukensis, n. sp. TeJlina (Angidus) valtonis,
Hanley. Tellina (Arcojyagia) j^^reiioscf,
Deshayes. Tellina ( f) rJiomboides,
Quoy and Gaimard. Tellina ( f) tenuilirata,
Sowerby. Tellina ( ?)Jijiensis, Sowerby.
Tellina ( ?) semen, Hanley.
Cardium (Acanthocardium) suezi- ense, Issel.
Cardium [Bucardium) australe, Sowerby.
Lucina (Codakia) levukana, n. sp.
Lucina (Codakia) Jijiensis, n. sp.
Lucina (Loripes ?) gordoni, u. sp.
Cryptodon rufolineata, u. sp.
Mytilus magellanicus, Chemnitz.
Septtifer hiloctdaris, Linne.
Area (Barhatia) fusca, Bruguiere.
Leda micans. A. Adams.
Lima (Ctenoides) tenera, Chem- nitz.
Station 184.— August 29, 1874 ; lat. 12° 8' S., long. 145° 10' E.: depth, 1400 fathoms; bottom, Globigerina ooze (east of Cajie York, North Australia).
Teredo sp.
Myrina coppingeri, n. sp.
A7-ca (Barhatia) corpulenta, n. sp. Pecten murrayi, n. sp.
REPORT ON THE LAMELLIBRANCHIATA.
17
Station 185.— August 31, 1874; lat. 11° 35' 25" S., long. 144° 2' E. ; depth, 135 fathoms; bottom, coral sand (east of Cape York, North Australia).
Tellina (• ?) d'duta, n. sp.
Semele {Abra) regidaris, n. sp. Verticordia deshayesiana, Fischer. Verticordia australiensis, n. sp. NecBra fallax, n. sp.
Station 185b.— August 31, 1874; lat. 11° 38' 15" S., long. 143° 59' 38" E fathoms; bottom, coral sand (east of Cape York, North Australia).
Poromija australla, n. sp. Poromija Icevis, n. sp. Nucula torresi, n. sp. Leda watsoni, n. sp. Leda necBriformis, n. sp.
depth, 155
Tellina murrayi, n. sp. Montacuta acuminata, n. sp. I/iicina cristata, n. sp.
Lucina (Codakia) congenita, n. sp. Limopsis torresi, n. sp. Amussium torresi, n. sp.
Station 186.— September 8, 1874 ; lat. 10° 30' S., long. 142° 18' E.; depth, 8 fathoms; bottom, coral mud (Cape York).
Circe ohliquissima, n. sp. Venus {Chione) foliacea, Philippi. Chamajukesii, Eeeve. Tridacna crocea, Lamarck. Gastrochcena lameUosa, Deshayes. Corbida monilis, Hinds.
Lima (Limatula) torresiana, n. sp
Station. — Cape York, in 3 to 12 fathoms. Circe fastigiata, Sowerby. Psammobia anomala, Deshayes. Tellina [Aiigidus?) rhomhoidcs,
Quoy and Gaimard. Mactra {Mactrinida) pUcataria,
Linne. Cardiu m (Fragum) imhricatum,
Sowerby.
Mytilus (Stavelia) horridus, Dunker. Lithodomus malaccanus, Reeve. Area (Barhatia) lima. Reeve. Limopsis caiicellata, Reeve. Avicnla macroptera, Lamarck. Spondylus zonalis, Lamarck.
Lucina {Divaricella) irpex, n. sp. Mytilus sidcatus, Lamarck. Trigonia uniopJiora, Gray. Area navicular is, Bruguiere. Limopsis cancellata, Reeve. Malleus albv^, Lamarck. Avicula {Meleagrina) dina, Reeve.
smarag-
Station.— Flinders Passage, north of Cape York ; depth, 7 fathoms.
Dosinia histrio, Gmelin. Petricola lapicida, jun.
Tellina ( ?) tenuilirata,
Sowerby.
Tellina ( '?*) languida, n. sp.
Tellina ( f) semen, Hanley.
Semele infans, n. sp.
(ZOOL. CHALL. EXP. PART XXXV. 1885.)
Myodora trigona, Reeve.
Myodora sp.
Mya sp.
Ccelodon elongata. Carpenter.
Diplodonta, subglobosa, n. sp.
Diplodonta conspicua, n. sp.
Limopsis cancellata, Reeve.
Mm 3
1!
THE VOYAGE OF H.M.S. CHALLENGER.
Station. — Torres Strait; depth, 3 to 11 fathoms.
Dosinia sculptd, Hauley. Cytlierea [Carr/atis) coxeni, Smith. Ci/th erea ( Gary a tis) regularis, n. sp. Circe scripta, Linud. Venus (Antigona) lamcllaris,
Schumacher. dementia papyracea, Gray. Tellina (Arcopagia) elegantissima,
n. sp.
Tellina (- Tellina (-
f) casta, Hauley. ?) langvida, n. sp.
Clavagella torresi, n. sp. Corhula crassa, var. Corhula scajjJwides, Hinds. Diplodonta conspicua, n. sp. Area {Scapharca) clathrata, Eeeve. Area (Trisis) semitoi'ta, Lamarck. Nucula ohliqua, Lamarck.
Station 187.— September 9, 1874 ; kt. 10° bottom, coral mud (Torres Strait).
Dosinia deshayesii, A. Adams. Dosinia histrio, Gmelin. Venus torresiana, Smith. Venus (Chione) foliacea, Phil-
ippi. Venus {Chione) calophylla, Phil-
ippi- Vemcs [Chione) infans, u. sp.
Venus ( Gomphina) undulosa,
Lamarck.
Tellina compacta, n. sp.
Tellina ( ?) semen, Hauley.
36' S., long. 141° 55' E.; depth, 6 fathoms;
Donax nitidus, Deshayes. Chama sidphurea, Reeve. Myodora, sp. (also Station 188). Corhula monilis, Hinds. Diplodonta scalpta, n. sp. Diplodonta corpulenta, n. sp. Diplodonta subglobosa, n. sp. Diplodonta conspicua, n. sp. Crassatella rhoniboides, n. sp. Area imhricata, Bruguiere. Avicula (Meleagrina) muricata, Eeeve.
Station 188.— September 10, 1874; lat. 9° 59' S.^ bottom, green mud (south of New Guinea).
Cytherea (Caryatis) regularis, n. sp. Circe australis, Sowerby. Circe gibhia, Lamarck. Circe jucunda, n. sp. Venus (Chione) foliacea, Pliilippi. Venus (Chione) lionota, n. sp. Venus (Chione) infans, n. sp. Tapes (Paratapes) semirugata,
Pbilippi. Psammobia pallida, Desbayes.
long. 139° 42' E.; depth, 28 fathoms;
Tellina ( ?) tenuilamellata,
n. sp. Myodora sp. (also Station 187). Cardium (Bucardium) multi-
spinosum, Sowerby. Cardium (Fragum) torresi, n. sp. Solen (Azor) coarctatus, Gmelin. Corbida macgillivrayi, n. sp. Corbida monilis. Hinds. Montacuta paula, A. Adams.
REPORT ON THE LAMELLIBRANCHIATA.
19
Station 188 — continued.
Lucina [Codakia) semimda, Gould. Lucina {Codakia) pisuin, Reeve. Lucina (Loripes) desiderata, n. sp. Dijdodonta corpulenta, n. sp. Diplodonta conspicua, n. sp. Canlita insignis, n. sp. Carditella torresi, n. sp. Car'ditella infans, n. sp. Crassatella rhomboides, u. sp. Crassatella torresi, n. sp.
Trigonia iiniop>hora, Gray. Pectuncidus vitreus, Lamarck. Limopsis cancellata, Reeve. Nuc^da ohliqua, Lamarck. Leda novce-guineensis, n. sp. Leda corhidoldes, n. sp. Spondylus victorice, Sowerby. Amussium pleuronectes, Linne. Amussium scitulum, n. sp. Ostrea imhricata, Lamarck.
Station 189.— September 11, 1874 ; lat. 9° 36' S., long. 137° 50' E. ; depth, 25 fathoms ; bottom, green mud (Arafura Sea).
Dosinia histrio, Gmelin.
Dosinia mira, n. sp. '
Tapes (Paratapes) undulata,
Born. Tellina (Angulus) lux, Hanley. Semele amabilis, A. Adams.
Cardium [Bucardiinn) nndtispin-
osum, Sowerby. Necera elegans. Hinds. Corhida tunicata. Hinds. Trigonia uniophora, Gray. Area (Scapharca?) consociata,ii. sp.
Leda lata, Hinds.
Station 190.— September 12, 1874 ; kt. 8° 56' S., long. 136° 5' E. ; depth, 49 fathoms ; bottom, green mud (Arafura Sea).
Tellina {Macoma) arafurensis,n. sp. 1 Martesia striata, Linne.
Station 191.— September 23, 1874; lat. 5° 41' S., long. 134° 4' 30" K; depth, 800 fathoms ; green mud (near the Arrou Islands).
Modiola watsoni, n. sp. | Nucula sp.
Malletia arrnana, n. sp.
Station. — Banda Islands; depth, shallow water. Cytherea (Dione) pliilippinarum, Hanley.
Mactra [Trigonella decoi^a), juu.
Station 194.— September 29, 1874; lat. 4° 34' S., long. 129° 57' 30" E.; depth, 200 fathoms; bottom, volcanic mud (south of the Molucca Islands).
Area (Barhatia) corpidenta, n. sp.
20 THE VOYAGE OF H.M.S. CHALLENGER.
Station. — Amboina, Molucca Islands; depth, 15 to 20 fathoms.
Venus (Chione) lionota, var. Tapes (Paremhola) ohscurata,
Dcshayes. Psammobia sp. Tellina (Angulus) vernalis,
Hanley. Tellina (Macoma) consociata,
n. sp. Semele [Theora) iridescens, Hiuds.
Corhda tunicata, Hinds. Corhula modesta, Hinds. Liicina (Codakia) sp. jiin. Cryptodon bidhda, Eeeve. Dijflodonta amboinensis, u. sp. Area (Barbatia) sculptilis, Reeve. Area (Seapharca) clathrata,
Reeve. Plicatida sp.
Station 198.— October 20, 1874; lat. 2° 55' N., long. 124° 53' E.; depth, 2150 fathoms ; bottom, blue mud (off the north-east point of Celebes).
Area {Barbatia) corpulenta, n. sp.
Station 201.— October 26, 1874; lat. 7° 3' N., long. 121° 48' E.; depth, 82 fathoms; bottom, stones, gravel (off the west coast of Mindanao, Philippine Islands). Venus [Chione) mindanensis, n. sj). | Area (Acar) eongenita, n. sp.
Lima lata, n. sj?.
Station. — Off Samboangan, Philippine Islands; depth, 10 fathoms.
Perna samoensis, Baird. | Pecten lemniscatus, Reeve (?).
Station 203.— October 31, 1874; lat. 11° 6' N., long. 123° 9'E.; depth, 20 fathoms; bottom, mud.
Peeten senatorius, var. Amussium pleuroneetes, Linn^.
Venus [Chione) calophylla, Philippi. Cardium [Bucardium) mirabile, Deshayes.
Station 204.— November 2, 1874; lat. 12° 28' N., long. 122° 15' E.; depth, 705 fathoms; bottom, green mud (off the west coast of Luzon, Philippine Islands).
Peeten vitreus, Chemnitz.
Station 205.— November 13, 1874; lat. 16° 42' N., long. 119° 22' E.; depth, 1050 fathoms; bottom, blue mud (same as preceding Station).
Cryptodon luzoniea, n. sp.
Station 207.— January 16, 1875; lat. 12° 21' N., long. 122° 15'E.; depth, 700 fathoms; bottom, blue mud (west of the Island of Luzon).
Modiola ivatsoni, n. sp. | Pecten vitreus, n. sp.
Amussium caducum, n. sp.
REPORT ON THE LAMELLIBRANCHIATA.
21
Station 208.— January 17, 1875; kt. 11° 37' N., long. 123° 31' E.; depth, 18 fathoms; bottom, bhxe mud (same as Station 204).
Chama cardit(Bfo7-mis, Eeeve. Anatina siphonata, Eeeve.
Cardium (Bvcardivvi) tenuicos-
tatum, Lamarck. Cardium {Bucardiiim) aiidrale,
Sowerby.
Diplodonta suhgramdosa, n. sp. Area (Barbatia) lima, Reeve. Pecten leopai-dus (var. Solaris). Pecten senatoriits, var.
Station 209.— January 22, 1875 ; lat. 10° 14' N., long. 123° 54' E. ; depth, 95 fathoms; bottom, blue mud (east of the Island of Panay, Philippines).
Pecten viirens, Chemnitz.
Station 210.— January 25, 1875 ; lat. 9° 26' N., long. 123° 45' E. ; depth, 375 fathoms; bottom, blue mud (same position as Station 209).
Semele (Abt'a) philippinensis, n. sp. | Amussium jeffreysii, n. sp.
Station 212.— January 30, 1875 ; lat. 6° 54' N., long. 122° 18' E. ; depth, 10 fathoms; bottom, sand (south of the Island of Mindanao).
Cytherea {Callista) Ulacina,
Lamarck. Cytherea (Callista) roseotincta, n. sp. Cytherea (Caryatis) hebrcea,
Lamarck. Cii'ce sulcata, Gray. Venus (Chione) recognita, n. sp.
Mactra (Trigonella) incarnata,
Deshayes. Cardium setosum, Redfield. Cardita canalicidata, Reeve. Area [Scapharca) angieostata,
Reeve. Pectunculus st7-iatidaris,hamsLTck (?).
Lima squamosa, Lamarck.
Station 216.— February 16, 1875; lat. 2° 46' N., long. 133° 58' E. ; depth, 1675 fathoms ; bottom, Globigerina ooze (north-west of New Guinea).
Ai-ca (Barbatia) corpulenta, n. sp.
Station 218.— March 1, 1875; lat. 2° 23' S., long. 144° 4' E. ; depth, 1070 fathoms; bottom, blue mud (north of New Guinea).
Amussium watsoni, n. sp.
Station 219.— March 10, 1875; lat. 1° 54' S., long. 146° 39' 40" E. ; depth, 150 fathoms ; bottom, coral mud (a little north-east of Station 218).
Cryptodon watsoni, n. sp.
22 THE VOYAGE OF H.M.S. CHALLENGER.
Station. — Admiralty Islands; depth, IG to 25 fathoms.
Mactra [Trigondla) achatina, Chemnitz.
Mactra (Trigonella) incerta, n. sp.
Station 232.— May 12, 1875; lat. 35° 11' K, long. 139° 28' E. ; depth, 345 fathoms; bottom, green mud (Gulf of Yedo, Japan).
Limopsis pelagica, u. sp. Nucula niponica, n. sp.
Yoldia lischkei, n. sp. Pecten vitreus, Chemnitz.
Station. — Off Yokohama, Japan; depth, 8 to 14 fathoms.
Raeta pulchella, A. Adams and Eeeve.
Station 233a.— May 10, 1875; lat. 34° 38' N., long. 135° 1' E.; depth, 50 fathoms; bottom, sand (between the islands of Sikok and Nipon, Japan).
Venus (Chione) scahra, Hanley. Tapes {Chione) undulata, Born. Modiola harhata, Liune. Area (Maerodon) dalli, n. sp.
Nucula (Acila) mirahilis, Adams
and Eeeve. Pecten (Janira) laqueatus,
Sowerby.
Anomia laqueata, var.
Station 233c.— May 28, 1875; lat. 34° 18' K, long. 133° 21' E.; depth, 12 fathoms; bottom, blue mud (same as preceding Station).
Paeta pulchella, Adams and Eeeve.
Station 236.— June 5, 1875; lat. 34° 58' N., long. 139° 29' E.; depth, 775 fathoms; bottom, green mud (south-east of Nipon, Japan).
Lima goliath, Sowerby.
Station 244.— June 28, 1875; lat. 35° 22' N., long. 169° 53' E.; depth, 2900 fathoms; bottom, red clay (Mid North Pacific Ocean).
Semele (Abra) profimdorum,!!. SI). | Callocardia {?) pacifica, n. sp.
Station 246.— July 2, 1875; lat. 36° 10' N., long 178° E.; depth, 2050 fathoms; bottom, Globigerina ooze (Mid North Pacific Ocean).
Area [Barhatia) pteroessa, n. sp. | Nucidd profundorum, n. sp.
Sarep)ta ahyssicola, n. sp.
Station. — ^Honolulu, Sandwich Islands (off the reefs in 40 fathoms).
Circe jucunda, n. sp. Ervilia sandwichensis, n. sp.
Liicina (Codakia) hawaiensis, n. sp. Julia exqu'isita, Gould.
REPORT ON THE LAMELLIBRANCHIATA. 23
Station. — Honolulu; depth?
Ervilia hisculpta, Gould. | Perna samoemis, Baird.
Station. — Hilo, Sandwich Islands ; depth?
Perna vitrea, Eeeve.
Station 271.— September 6, 1875; lat. 0° 33' S., long. 151° 34' W.; depth, 2425 fathoms; bottom, Globigerina ooze (Mid Pacific Ocean).
Area (Barhatia) corpulenta, n. sp.
Station. — Tahiti ; depth, 20 to 40 fathoms.
Cytherea (Dione) philijypinarum, Hanley.
LiTna tahitensis, n. sp.
Station 281.— October 6, 1875; lat. 22° 21' S., long. 150° 17' W. ; depth, 2385 fathoms ; bottom, red clay (Mid South Pacific Ocean, south of Tahiti).
Sarepta abyssicola, n. sp.
Station 300.— December 17, 1875; lat. 33° 42' S., long. 78° 18' W.; depth, 1375 fathoms; bottom, Globigerina ooze (a little north-east of Juan Fernandez).
Area (Barbatia) corpulenta, n. sp.
Station 302.— December 28, 1875; lat. 42° 43' S., long. 82° 11' W.; depth, 1450 fathoms; bottom, Globigerina ooze (about 600 miles west of Chili).
Amussium meridionale, n. sp.
Station 305.— January 1, 1876, lat. 47° 47' S., long. 74° 47' W.; depth, 165 fathoms; bottom, blue mud (ofli" the west coast of Patagonia).
NecBra patagonica, n. sp.
Station 307.— January 4, 1876; lat. 49° 24' 30" S., long. 74° 23' 30" W.; depth, 140 fathoms ; bottom, blue mud (off the west coast of Patagonia).
Pecten vitreus, Chemnitz.
Station 308.— January 5, 1876; lat. 50° 8' 30" S., long. 74° 41' W.; depth, 175 fathoms; bottom, blue mud (same as Station 307).
Pecten vitreus, Chemnitz.
24 THE VOYAGE OF H.M.S. CHALLENGER.
Station 310.— January 10, 1876; lat. 51° 27' 30" S., long. 74° 3' AV.; depth, 400 fathoms; bottom, blue mud (off the west coast of Patagonia).
Pecten vitreus, Chemnitz. | Pecten suhhyalinus, n. sp.
Station 311.— January 11, 1876; lat. 52° 45' 30" S., long. 73° 46' W.; depth, 245 fathoms; bottom, blue mud (off west coast of Southern Patagonia).
Saxicava arctica, Linne. Modiolarca trapezina, Lamarck.
Solemya patagonica, u. sp. Pecten vitreus, Chemnitz.
Lucina lamellata. Smith. Lima goliath, Sowerby.
Station 312.— January 13, 1876; lat. 53° 37' 30" S., long. 70° 56' W.; depth, 9 fathoms; bottom, blue mud (Strait of Magellan).
Pecten patagonicus, King.
Station 313.— January 20, 1876; lat. 52° 20' S., long. 67° 39' W.; depth, 55 fathoms; bottom, sand (east of the entrance to the Strait of Magellan).
Saxicava arctica, Linne.
Station 315.— January 26, 1876; lat. 51° 40' S., long. 57° 50' W.; depth, 12 fathoms (off the Falkland Islands).
Mijtilus ediilis, Linn^.
Mytilus magellanicus, Chemnitz.
Modiolarca trapezina, Lamarck. Pecten piatagonicns, King.
Station 316.— February 3, 1876; lat. 51° 32' S., long. 58° 6' W. ; depth, 4 fathoms; bottom, mud (off the Falkland Islands).
Venus (Katelysia) exalhida, Chem- nitz.
Cryptodon falhlandica, n. sp.
Station 317.— February 8, 1876; lat. 48° 37' S., long. 55° 17' W.; depth, 1035 fathoms; bottom, hard ground (gravel) (north of the Falkland Islands).
Lima (Limatula) sp.
Station 320.— February 14, 1876; lat. 37° 17' S., long. 53° 52' W.; depth, 600 fathoms; bottom, green sand (off the coast of La Plata).
Neoera platensis, n. sp.
REPORT ON THE LAMELLIBRANCHIATA. 25
Station 321.— February 25, 1876; lat. 35° 2' S., lung. 55° 15' W.; depth, 13 fathoms; bottom, mud (mouth of the Rio de la Plata).
Cytherea (Caryatis) rostrata,
Koch Tellina (Macoma) uruguayensis,
n. sp.
Mactra {Trigonella) isahelliana,
d'Orbigny. Periploma compressa, d'Orbiguy. Nucula uruguayensis, Smith.
Station 322.— February 2G, 1876; lat. 35° 20' S., long. 53° 42' W.; depth, 21 fathoms; bottom, sand, shells (off the mouth of the Rio de la Plata).
Mytilus edulis, Linne. | Plicatula r-ainosa, Lamarck.
Station 323.— February 28, 1876; lat. 35° 39' S., long. 50° 47' W. ; depth, 1900 fathom.s; bottom, blue mud (east of the preceding Station).
Glomus nitens, Jeffreys.
Station 325.— March 2, 1876 ; lat. 36° 44' S., long. 46° 16' W.; depth, 2650 fathoms; bottom, blue mud (farther east than Station 323).
Silenia sarsii, n. sp.
Station 344.— April 3, 1876; lat. 7° 54' 20" S., long. 14° 28' 20" W.; depth, 420 fathoms ; bottom, volcanic sand (off Ascension Island).
Cryptodon sp. | Leda Jeffrey sii, Hidalgo.
Station 348.— April 9, 1876; lat. 3° 10' N., long. 14° 51' W.; depth, (2450) fathoms; bottom, Globigerina ooze (south of Sierra Leone).
Callocardia (f) adamsii, n. sp.
(ZOOL. CHALI.. EXP. — PART XXXV. — 188-5.) Mm 4
DESCRIPTIONS OF SPECIES.
Order LAMELLIBRANCHIATA.
Family Pholadid^.
Subfamily Teredinin^.
Teredo, Linne. Teredo sp. Habitat. — Station 184, east of Cape York (in 1400 fathoms ?) ; Globigerina ooze.
A single very small specimen, all that was obtained, may possibly be the young state of the Teredo mentioned in the Eeport of the collections made during the Voyage of H.M.S. "Alert" in Torres Strait. The striae on the anterior part of the valves are, however, rather coarser. Although from Station 184, to which a depth of 1400 fathoms is assigned, it seems probable that this sheU, which contained the animal, got into the trawl near the surface, during the process of hauling in. This, however, is not certain, for water-logged wood might be found at that depth into which it might bore.
Subfamily PnoLADiNiE. Martesia, Leach.
Martesia striata (Linne).
P?wlas striata (Linne), Sowerby, Thesaurus Conch., vol. ii. p. 494, pi. civ. figs. 40-42, pL cv.
figs. 43, 44. Pholas striata, Sowerby, Conch. Icon., vol. xviii. figs. 32a-c. MaHesia striata, II. ami A. Adams Genera, vol. iii. pi. xc. figs. 5, 5a.
Habitat. — Station 190, Arafura Sea, in 49 fathoms; green mud.
Specimens from this locality present very slight if any variation in sculpture, but difl'er somewhat in the length of the hinder prolongation of the valves, and in the form of the anterior dorsal plate.
28 THE VOYAGE OF H.M.S. CHALLENGER.
Subfamily (iASTROCH^NiN^. Gastrochcena, Spengler. Gastrochcena lamellosa, Desliayes (PI. VIII. figs. 2-2&).
Gastrochcena lamellosa, Deshayes, Proc. Zool. Soc. Lond., 1854, p. 328. Gasfrochceiia lamellosa, Sowerby, Conch. Icon., vol. xx. fig. 14 (bad !).
Habitat. — Station 18G, off Cape York, in 8 fatliom.s (Challenger); coral mud; Island of Zebu, Philijipines (Cuming).
The figure in Sowerby's Monograph is not at all accurate, neither as regards the form- of the gape nor the opposite extremity. The figure now given is taken from the type specimen in the British Museum.
Gastrochcena duhia (Pennant).
My a duhia. Pennant, Brit. Zool., voL iv. p. 88, pi. xliv. fig. 19.
Gastrochcena rnodiolina, Lamarck ; Forbes and Hanle}', Brit. Moll., vol. i. p. 132, pi. ii. figs. 5-8,
and PI. F. fig. 5 (animal). Gastrochcena duhia, Deshayes, Traits Elem. Couch., pi. ii. 6gs. 4, 5. Gastrochcena duhia, Jeffreys, Brit. Conch., vol. iii. p. 91, vol. v. pi. Ii. fig. 6. Gastrochcena dubia, Hidalgo, Molusc. Espaiia, pi. xlix. figs. 3, 4.
Habitat. — Harbour of St. Vincent, Cape Verde Islands and Tenerife, Canaries, in 70 fathoms.
This species, ranging from the southern coasts of England to the Mediterranean, Madeira, and Canary Islands, has not, I believe, hitherto been noticed so far south as the Cape Verde Islands. The single specimen from that locality is a trifle more elongate than those from Tenerife.
Subfamily Clavagellin.e. Clavagella, Lamarck.
Clavagella torresi, n. sp. (PL VIII. figs. l-\h).
Testa parva, tenuis, allia. Valva liliera valde insefjuilateralis, antice late rotundata, postice paulo angustior, lineis incrementi subrugosis sculpta, liris tenuissimis granulosis radiantibus umbones versus ornata. Pagina interna nitens, concentrice alicpianto rugosa, radiatim indistincte substriata. Ligamentum internum parvum, oblicj[Uum, postice deuticuh > minuto terminatum. Tubus inferne irregulariter ovatus, superne valde constrictus ct angustatus, ad basim c[uoque ad latera tubulis multis instructus.
REPORT ON THE LAMELLIBRANCHIATA. 29
Of this small species only a single specimen was dredged. The lower portion of the tube is somewhat ovate, and broader at the inferior end. Above it is rather suddenly- contracted into a small, i)lain tube, which is partly partitioned off within, from the main cavity, leaving only a narrow elongate opening of communication. The base and sides of the swollen portion of the tube are ornamented with numerous short tubuli. The interior of the tube is strengthened on the side of the free valve by a slender central ridge passing from the umbo of the fixed valve up the opposite side. The free valve is longer than high, considerably inequilateral, thin, white, very compressed, broadly rounded anteriorly, narrowed and produced behind. It is marked with rather coarse lines of growth, and ornamented at the upper part with very fine granular lines which radiate from the umbo not quite half-way across the valve. The beak is small, acute, slightly raised above the hinge line, and situated considerably in advance of the centre. The interior is glossy, somewhat wrinkled concentrically, and faintly substriated in the opposite direction. The muscular scars and pallial sinus are very indistinct. Just behind the apex of the umbo, and within the dorsal edge, there is a minute narrow groove terminated behind by a small denticle which receives a minute ligament.
Length of free valve 12 mm., height 8; greatest width of tube 9, smallest width 4; length of opening of communication between the narrow and swollen portions of the tube 3, width 1.
Habitat. — Torres Strait, in 3 to 11 fathoms.
Family Myidje.
Subfamily Corbulin.e.
Corbitla, Bruguiere.
Corhida tunicata, Hinds.
Corhula tunicata, Hinds, Proc. Zool Soc. Lond., 1843, p. 55.
Corhula tunicata, Reeve, Conch. Icon., vol. ii. fig. 5.
Corhula tunicata, Tryon, Amer. Journ. Concli., vol iv. Appendix, p. 66.
Habitat. — -Port Jackson, Sydney, in 4 to 18 fathoms; off Amboina, in 15 to 25 fathoms; and Station 189, Arafura Sea, in 25 fathoms; green mud.
The specimens from the first two Stations are fine large shells agreeing in every particular. The largest example is 28 mm. long, 19^ high, and 16 in diameter. Two specimens from the Arafura Sea are somewhat abnormal both in form and sculpture, occupying an intermediate position between this species and Corbida crai^m. The latter species is more equivalve than Corbida tunicata, has the left valve sculptured throughout like the right, which has a much smaller and less curved-over umbo than that of the
30 THE VOYAGE OF H.M.S. CHALLENGER.
present form. On the contrary, the left or smaller valve of Corhula tunicata has only the earlier portion strongly ridged, the rest of the surface exhibiting only lines of growth coated with a fibrous epidermis. The contrast between the two styles of ornamentation is so marked that the valve presents the appearance of having the umbonal portion of a differently sculptured species fixed on to its own smoother surface. The peculiarity, in the two specimens from the Arafura Sea, consists in their having a much larger proportion than usual of this valve strongly sculptured. In one there is scarcely any cessation of the concentric ridging, whilst in the other it extends over about two thirds of the surface. The ridges in this species are both more numerous and more rounded than in Corhula crassa, which also presents another distinction in very adult examples that is never met with in any specimens of any age of Corhula tunicata. I refer to the presence of fine denticulation upon the dorsal and ventral margins of the left valve. A still closer approach to the present species is met with in Corhula sulcata from West Africa. Here is a species which not only has the same form, but offers scarcely any difference in sculpture, and is mainly distinguished by a variation in colour.
Corhula crassa, Hinds, var.
Corhula crassa, Hinds, Proc. Zool. Soc. Lond., 1843, p. 53. Corhula crassa, Keeve, Conch. Icon., vol. ii. figs. 8 a-c.
Habitat. — Torres Strait, in 3 to 11 fathoms (Challenger); Port Essington (J. B. Jukes, Esq., in Brit. Mus.); Straits of Macassar, Malacca (Hinds) ; Bai.s, Island of Negros, Philippines (Cuming).
The specimens from the above localities are somewhat different from the normal form found at the Philippine Islands. In stoutness and outline they correspond very closely, but are at once distinguished by the microscopic sculpture. The entire surface of the valves is covered with a dense mass of minute circular granules, arranged more or less regularly in closely packed radiating series. In the typical form the rows of granules, which are of the same character, are much farther apart, and the apices of the valves are smoother than in the variet)^ which has the concentric ribs developed somewhat earlier. Beyond these differences there does not appear an}^ reason for separating these two forms.
Corbula macgillivrayi, n. sp. (PI. X. figs. 8-8?>).
Testa magna, elongata, crassa, albida, paulo insequivalvis, valde insequilateralis, antice rotundata, postice oblique truncata, ad extremitatem acute angulata, concentrice costata, et radiatim minute granulato-striatn, costis ])one carinam ab umbone ad extremitatem
REPORT ON THE LAMELLIBRANCHIATA. 31
posticam decurrexitem tenuioribus, umbonesque versus subobsoletis. * Margo dorsi antifus valde obli(|uus, subcoucavus, posticus minus declivis, fere rectilinearis, elongatus. Margo ventris in medio late sinuatus, utrinque leviter excurvatus. Umbones parum prominentes, albi vel rubeseentes, Isevigati. Pagina interna alba, plus minusve olivaceo- fusco maculata, margine exterior! valvse sinistrse in testis adultis liic iUie minute denti- oulato. Dens cardinis valvse dextrte erectus, aeutus.
This is a large species, very long, not particularly convex, whitish, only slightly inequivalve, but very inequilateral. It is nearly twice as long as high, rounded at the anterior end, obliquely and sharply truncated behind, terminating in an acute point. The valves are moderately thick, and divided into two unequal parts l)y a sharp keel ranning obliquely from the beaks to the hinder extremity. They also exhibit a shallow depression down the middle, causing a sinus or incurvation in the ventral margin, which otherwise is slightly arcuate. The dorsal slopes are unequal, the anterior being short, very oblique and faintly concave, the posterior longer, less descending and nearly rectilinear. The sculpture (consists of moderately strong, concentric ridges, which gradually increase in thickness with, the growth of the shell, becoming behind the radiating carina slighter than in front. In addition, the entire surface exhibits very numerous, excessively fine, radiating lines, which are minutely granular, especially conspicuous in the grooves between the costae. The beaks are only a little prominent, curve over towards the front, and are almost smooth at the tips, which are usually white, but at times pinkish. The single cardinal tooth of the right valve is erect, curved, and acute. The interior of the valves may be either almost totally white, or more or less stained with olive-brown, or occasionally with a pinkish tint. The margin of the left valve in old specimens is more or less minutely denticulated aU round, a corresponding groove just ^\ithin the circumference of the right valve being minutely pitted.
Length 26 mm., height 13, diameter 9.
Habitat. — Station 188, south of New Guinea, in 28 fathoms; bottom, green mud.
Young shells of this species and of Corhula scaphoides are very much alike. The latter are, however, flatter, more inequilateral, and have fewer and less elevated ridges, which are much more obsolete behind the oblique keel.
This species is not likely to be mistaken for any other on account of its large size and very elongate form. Corhula crassa offers some resemblance, but is proportionally higher, more ec^uilateral, thicker, more coarsely ridged towards the umbones, more suddenly contracted at the posterior or rostrated extremity, and has stronger hinge characters.
32 THE VOYAGE OF H.M.S. CHALLENGER.
Corhula scaphoides, Hinds (PI. Ylll. figs. 3-3Z>).
Curhida scapJtoiden, IliiiJs, Proc. Zool. Soc. LoniL, 184.3, p. 5G. Ciirhula scaphoides, Reeve, Concli. loon., vol. ii. tig. 2-t.
Habitat — Torres Strait, in 3 to 1 1 fathoms (Challenger) ; Singapore and Philippine Islands (Hinds), Hong Kong Harbour (Bowring).
The specimens described by Hinds were apparently only the young of this species, judging from a single right valve obtained by the Challenger. This valve bears a considerable resemblance to the dee]) one of Corhula tunicata or Corhula sulcata, but is much broader at the upper part, tlie young shell being much more elongate in this species than in either of those mentioned. It is 25 mm. long, 17 high, and as deep as that of Corhula tunicata. The young shell, about 13 mm. in length, forms as it were an umbonal cap as in many species of this genus. From this point the concentric ridges gradually thicken, and are more or less undulating. They are attenuated anteriorly, and become more slender and closely packed at the carina, which runs from the beak to the posterior extremity, which is much narrowed, and has a pinched or nasute appearance. In young shells the surface is also ornamented with numerous excessively fine radiating granular lirse, which are not, however, traceable in the single adult valve, as the surface is too much worn. The hinder muscular scar is situated on a shelf-like projection, this feature being also noticeable in the young shells.
In the British Museum there is a single adult specimen of this species from Hong- Kong Harbour, presented by J. C. Bowi'ing, Esq. This is in perfect condition, but not quite as large as the Challenger valve. There certainly is a very close relationship between this species and Corhula tunicata, the main distinction consisting in the much longer umbonal portion of the valves in the present form. Both have exactly the same kind of radiating series of minute circular granules, the epidermis covering the lower half of the left valve is similar in both forms, and the muscular impressions are not very dissinailar, although in Corhula scaphoides the posterior stands out rather more than that of Corhula tunicata. Both have exactly the same stout, curved, and acute cardinal tooth in the deep valve, and their external ribbing is also similar.
Corhula modesta, Hinds.
Corhida modesta, Hinds, Proc. Zool. Soc. Lond., 1843, p. .57. Corhida modesta, Reeve, Concli. Icon., vol. ii. fig. 14. Corhvla modesta. Smith, Proc. Zool. Soc. Lond., 1871, p. 728.
Hahitat. — Amboina, in 15 to 20 fathoms; also Station 172, off Nukalofa, Tongatabu, in 18 fathoms (Challenger); Philippine Islands and Malacca (Hinds); ^^^lydah, West Africa (Knocker).
REPORT ON THE LAMELLIBRANCHIATA. 33
Occasion lias already becu taken to remark upuu the great similarity existing between two species of this genus, the one {Curhula siiJcata) from the shores of Western Africa, the other {Corhula tunicoAa) from Amboina, the Philippines, North and East Australia. In the present instance I have to repeat tlie record of the existence of the very same shell from all these localities, with the exception of East Australia. A single example dredged by Captain Knocker, R.N., at Whydah, on the Dahomey shore, was referred to this species by myself in 1871. I have again most carefully examined it, and see no reason for altering that location. The apices of the umbones are of the same smooth porcel- lanous whiteness, bordered in front with a pinkish stain as in eastern specimens, the concentric ribbing is identical, the colour of the interior the same, and the hinge and muscular scars correspond in every respect.
If there were more specimens for examination, it is possible some distinguishing feature might present itself, but at present I feel certain of the identity of these shells from such widely remote and distinct zoological provinces.
Corhula pMlippii, n. sp. (PI. VIII. figs. 4-46).
Testa parva, valde insequivalvis, insequilateralis, triangulariter ovata, alba, valva sinistra epidermide fibrosa prope marginem induta. Valvse crassiusculse, diverse sculptae. Valva dextra convexa, postice breviter rostrata, ad extremitatem truncata, obtuse bicarinata, costellis rotundatis, crassiusculis, concentricis, prope carinam anteriorem fere evanidis, instructa. Valva sinistra longe minor, incrementi lineis striata, liris paucis radiantibus ornata. Umbones valde prominentes, involuti, nivei, l?evigati. Linea cardinis utrinque declivis, rectiuscula, fusco tincta.
This compact little species is very inequivalve, rather convex, somewhat inequilateral, triangularly ovate with the umbones well raised. The anterior end is sharply rounded, the posterior subrostrate, shortly and slightly obliquely truncate, the lower margin being well curved in front and at the middle, and very faintly incurved behind near the lower angle of the rostrum. It is w^hite with the exception of a slight tinge of brown upon the hinge- margin, chiefly behind the beaks, and the left valve is clothed more or less, principally towards the lower outline, with a yellowish fibrous epidermis. The right valve, which is far the larger, has an obtuse ridge running from the apex obliquely to the lower end of the hinder truncation, marking off" a definite and somewhat concave posterior area, and within this, close to the dorsal margin, it has a second less noticeable rounded carina. Its sculpture consists of rounded concentric ridges which gradually tliicken as the shell increases. They are numerous, broader than the intervening grooves, attenuated (in some instances obsolete) anteriorly, and become mere strise between the radiating cariu;e behind. The left valve merely exhibits fine concentric lines of growth and a few (about
(ZOOL. CHALL. EXP. PART .XXXV. — 1885.) Mm 5
34 THE VOYAGE OF H.M.S. CHALLENGER.
eight) inequidistant radiating ridges, wliicli do not, however, extend quite up to the beaks. These in both valves are smooth, rather glossy, almost snow-white, and well rolled in and forward. The right valve has a simple strong erect cardinal tooth immediately beneath the beak, which fits into a corresponding pit in the left valve, behind which is a stout process or denticle supporting the ligament. The interior is more or less stained with brown, the anterior scar elongate, the posterior rounder, and the pallial line faintly sinuated.
Length 6 mm., height 5 J, diameter 3f.
Habitat. — Station 33, off Bermuda, in 435 fathoms ; coral mud ; (Challenger) ; Hayti (Coll. Cuming in British Museum).
This interesting little species does not appear to agree with any of the numerous forms already described from the West Indian region. In the inequality of the valves it resembles Corbula ojyerculata, Philippi, from St. Thomas Island, but differs from that species in size, form, the absence of the double keel in the right valve, and in the difiierent sculpture of the left.
Corbula monilis, Hinds.
Corbula monilis, Hinds, Proc. Zool. Soc. Lond., 1843, p. 58. uorhula monilis, Eeeve, Conch. Icon., vol. ii. pi. v. fig. 35.
Testa minuta, alba, globosa, paulo inaequdateralis, antice rotundata, postice leviter producta, plus minusve truncata. Margo dorsi utrinque valde declivis, leviter arcuatus, ventralis late curvatus, postice paululum sinuatus. Valvse mediocriter tenues, valde insequales, liris concentricis gracilibus instructse. Umbones magni, inflati, prominentes, antrorsum curvati.
This species, several specimens of which were obtained, all of the same minute dimensions, is somewhat inequilateral, considerably inflated, moderately thick for so smaU a shell, white, inequivalve, and marked with fine concentric lirse. . The dorsal slopes are somewhat curved and very oblique, the ventral outline being slightly arcuate, and a little sinuated posteriorly. The anterior end is sharply rounded, the hinder extremity being a. little produced and somewhat truncated. The umbones are rather large, elevated above the hinge line, and terminate in a minute glossy tip curved over towards the front. The right valve has a single erect, strong tooth, immediately beneath the apex of the beak, and in the left there is a triangular pit for its reception.
Length 2 mm., height If, diameter 1^.
Habitat. — Stations 186, 187, and 188, all in Torres Strait, North Australia, in 3 to 28 fathoms.
This minute form was originally described from specimens collected at the island of Luzon. The largest of these Philippine examples is 2f mm. long, 2^ high, and 2 in diameter.
REPORT ON THE LAMELLIBRANCHIATA.
35
NecBra, Gray.
The number of species in this genus has very considerably increased of recent years, and although they have been subdivided to some extent by A. Adams/ and arranged into sections by Dr Gwyn Jeffreys,* some further revision ajjpears to be still requisite. Adams' arrangement is based partly on hinge-characters and partly on external features, that of Jeflreys being founded solely on differences of sculpture, the result being that shells are found in the same sections with others, the hinges of which are very different, e.g., Necera teres, Necera semistrigosa, Necera injiata, &c.
Having examined a large number of species, I have found certain differences in their hinges which may form the basis of a rearrangement, in submitting which, however, I at present refrain from naming the sections in which I have grouped the species, awaiting still further material, so that their validity and usefulness may be tested. Those species whose names are marked with an asterisk (*) have been located from description only, and not from personal examination.
Section A. (Necera proper).
Teeth. — A single more or less elongate lateral tooth on the posterior side 'in the right valve, none in the left.
Cartilage. — More or less obliquely inclined posteriorly. Surface. — Concentrically striate, lamellated, or costate.
Necera cuspidata, Olivi. rostrata, Spengier. obesa, Loveu. suhtorta, Sars. hindsiana, A. Adams. rosea, Hinds. circinata, Jeffreys. aiocarinata, kerg uelenensis,
plateiisis, angasi, meridi-
onalis, consociata, azorica,
capensis, patago7iica,wolla-
stonii, all n. sp. chinensis, Gray. latisidcata, Tenison-Woods. elegans, Hinds.
Necera arcuata, Dall (?)
Necera gracilis, Jeflfreys.
bicarinata, Jeffreys. depressa, Jeffreys. limatula, Dall (?) = con-
tracta, Jeffreys. ruginosa, Jeffreys. truncata, Jeffreys.' arctica, Sars.'"' glacialis, Sars.* jugosa. Wood.* papyria, Jeffreys.* exigua, Jeffreys.* nobilis, A. Adams.* nasiita, A. Adams.* trailli, Hutton.*
* Ann. and Mag. Nat. Hist., 1864, vol. xiii. p. 206. ^ Left valve only examineil.
2 Proc. Zool. Soc. Land., 1881, p. S.^B.
36 THE VOYAGE OF H.M.S. CHALLENGER.
Section B. — Subgenus Cardiomija , A. kA-M\\s = Spathophora, Jeffreys.
Teeth. — Same as in {Necera proper) Section A. Cartilage. — Less oblique than in the above. Surface. — Eadiately costate or Urate.
NecBva goukUana, Hinds. costeUata, Deshayes. fallax, n. sp. pectinata, Carpenter. costata, Sowerby.
Section O.
Necera concinna. Hinds. striata, Jeffreys. curta, Jeffreys. multicostata, Verrill and Smith.*
Teeth of right valve, Cartilage-Pit, and Sculpture, the same as in Section A, but a small erect posterior lateral tooth is present in the left valve.
Necera pulchella, H. Adams.
Section D.
Teeth. — One small lateral tooth on each side near the beak in both valves (the anterior in the left being feeble).
Cartilage and Surface as in A and B.
Necera singaporensis, Hinds.
Section E.
Teeth. — A short lateral tooth on each side in the right valve, with coiresjjonding pits in the hinge-margin of the left, more conspicuous on the anterior side than behind. Cartilage. — Obliquely inclined towards the posterior end. Surface. — Concentrically striated.
Necera teres, Jeffreys.
Section F.
Teeth. — A short erect lateral tooth on each side, and a small dentiform projection of the hinge-margin in front of the apex in the right valve, and a single tubercular denticle in front of the apex (but no laterals) in the left.
REPOET ON THE LAMELLIBRANCHIATA.
37
Cartilage. — Posteriorly inclined, not in a pit or process, but attached to the valves. Surface. — Concentrically striate. •
Necera hrazieri, n. sp.
Section Gt. — Subgenus Rhinomya, A. Adams.
Teeth. — One lateral tooth on each side in the right valve, none in the left. Cartilage. — Internal, attached to the valve under the beaks. Surface. — Concentrically striate.
Necera rugata, A. Adams.'"'
pliilippinensis, A. Adams {nee Hinds).
Necera notabilis, Jeffreys.*
lamellifera, Dall = semi- strigosa, Jeffreys.
Section H.
Teeth. — One small conical tooth in front of the umbo in the right valve, none in left : no laterals in either.
Cartilage. — Narrow, vmder apex, parallel with margin. Surface. — Concentrically striate.
Necera phiJippinensis, Hinds.
Section I.
Teeth. — A single denticle in both valves in front of the beaks ; no laterals. Cartilage. — Elongate, narrow, subparallel with the dorsal edge. Surface. — Concentrically plicate.
Necera abbreviata, Forbes.
Section J.
Teeth. — One small thickish tooth on each side in the right valve, and a similar one in the left, in front only.
Cartilage. — Very small, central. Surface. — Finely ridged.
Necera culuncct, Gould.
38 THE VOYAGE OF H.M.S. CHALLENGER.
Section K.
Teeth.-;— A. single acute denticle in the right valve in front of the cartilage-pit, and a long shelf-like process parallel with the posterior dorsal margin in each valve. Cartilage-Pit. — Small, central or oblique. Surface. — Concentrically striate.
NecBra claviculata, Dall. | Necera injlata, Jeffreys.
NeoBra congenita, n. sp.
Section L.
Teeth. — None in either valve.
Cartilage. — Small, oblong, attached to a thin shelly process and directed posteriorly.
Surface. — Concentrically lamellar or striated.
Necera angularis, Jeffreys. | Necsra sulcifera, Jeffreys.
Section M.
Teeth. — None in either valve. Cartilage. — Short, anteriorly inclined. Surface. — Eadiately costellate.
Necera fragilissima, n. sp.
The subjoined Table will show at a glance the considerable difference in the structure of the hinges of the subgenera or sections. In some cases the teeth appear to be the same, as in A and B, and L and M, but in these instances there are other differences in the cartilage or sculpture which constitute the chief points of distinction.
REPORT ON THE LAMELLIBRANCHIATA.
39
|
Right Valve. |
Left Valve. |
|||||
|
Sections. |
Anterior cardinal. |
Anterior lateral. |
Posterior lateral. |
Anterior cardinal. |
Anterior lateral. |
Posterior lateral. |
|
A |
X |
|||||
|
B |
X |
|||||
|
C |
X |
X |
||||
|
D |
X |
X |
X |
X |
||
|
B |
X |
X |
1 |
1 |
||
|
F |
X |
X |
X |
X |
||
|
G |
X |
X |
||||
|
H |
X |
|||||
|
I |
X |
X |
||||
|
J |
X |
X |
X |
|||
|
K |
X |
X2 |
X2 |
|||
|
L |
||||||
|
M |
The hinges of the following species are unknown to me, and therefore I have been unable to locate them in any of the proposed sections : —
Necera crassa, Monterosato.
tasraanica, Tenison- Woods. pura, Angas. granulata, Dall.
Nemra jeffreysi, Dall. casta. Hinds. didyma, Hinds. trigona, Hinds.
Section A.
Necera patagonica, n. sp. (PI. VHI. figs. 5-55).
Testa NewrcB wollastonii similis, sed crassior, paulo in?equilateralis, rostro postico longiori et graciliori desinita.
' Hinge margin with pits for reception of the teeth of the right valve.
2 These are hardly teeth, but rather elongate, shelf-like processes -nithin the hinge-margin.
40 THE VOYAGE OF H.M.S. CHALLENGER.
Length 29 mm., height 14, diameter 12.
Habitat. — Station 305, west coast of Patagonia, in 165 fathoms ; l)lue mud.
Both this species and Neceixt woUastonii may eventually prove to be large varieties of Ne(Bra rostrata, Spengler, being similarly sculptured. Still there is a considerable difference in form. The single left valve from the above locality has the apex of the umbo (viewing it from within) situated 13 mm. from the anterior end, or only one and a half in advance of the centre. From this it will be seen that it is more equilateral than Necera rostrata, but less so than Necera woUastonii.
NecBra ivollastonii, n. sp. (PI. X. figs. (j-Qh).
Testa magna, tenuis, alba, hand nitida, globosa, ovata, postice louge rostrata, incre- ment! lineis tenuibus striata. Margo dorsi auticus oblique arcuatus, posticus minus declivis, levissime concavus. Ventris margo antice et inferne late arcuatus, ad rostrum late sinuatus. Rostrum elongatum, marginibi;s subparallelis, carina obliqua leviter curvata dimidiatum, ad extremitatem posticam subrecte truncatum. Umbones magui, involuti, ad apicem sublsevigati, centrales. Pagina interna nitens, plus minusve radiatim substriata. Linea cardinis tenuis, subreflexa, sub umbone valvae sinistra^ loculo ligamentali parvo obliquo instructa.
This is a large thin shell, much inflated, ovate, and terminated behind in a long beak. It is white, with scarcely any gloss upon the surface, and sculptured with fine striae of growth only. The hinder dorsal margin is slightly oblique and the least concave, the anterior being arcuate and more sloping, but this depends u^ion the position in which the shell is regarded. The anterior end is semicircularly rounded, the ventral outline more broadly curved and widely sinuated at the commencement of the rostrum. This has the upper and inferior margins almost parallel, the extremity nearly abruptly truncate, and is obliquely bisected by a slight radiating ridge. The umbones are considerabl}^ elevated, exactly central, smoothish, and incurved at the tips. The hinge-line in the left valve is thin, a little expanded upwards on both sides of the umbo, immediately beneath which is a very small ligamental pit directed obliquely towards the hinder end. The interior is glossy,, and exhibits a distinct substriation about the central parts. The posterior muscular scar is elongate, and situated under the dorsal line not quite half-way from the umbo to the end of the rostrum.
Length 26 mm., height 14^, presumed diameter of the complete shell 12.
Habitat. — Station 73, a little west of the Azores, in 1000 fathoms ; Pteropod ooze.
I have named this species in remembrance of the late T. V. Wollaston, who contri- buted so much to our knowledge of the fauna of the islands of the Atlantic. It is a
REPORT ON THE LAMELLIBRANCHIATA. 41
larger shell than Necera rostrata, Spengler, although very similarly sculptured, and terminates in a much shorter posterior rostrum.
Neceixi consociata, n. sp. (PI. IX. figs. 7~7b).
Testa parva, tenuis, pellucida, globosa, postice subito rostrata ; rostrum breve, truncatum, increment! lineis subvalidis sculptum, carina obliqua distincta dimidiatum. Valvse antice rotundatse, inferne late arcuatje, postice prope carinam subprofunde sinuatae, lamellis brevibus paucis (circa decern) ornatse. Umbones Iseves, leviter prominentes, antemediani, fere in ^ longitudinis collocati. Cardo in valva sinistra edentulus, in dextra ? Fossa ligament! linearis, margine dorsali parallela, baud intus projecta.
This species must approach very closely Necera lamelUfera of Dall, and may indeed prove eventually to be the young state or a variety of it. It may, however, be at once distinguished from that species, which is only known to me by description, by the distinct keel, which, starting from the lower corner of the rostrum, curves up obliquely towards, but does not extend quite to, the umbones. The latter, too, are apparently placed more forward, being just a shade more than one-third of the total length from the anterior end, whilst in Necera lamelUfera they appear to be very little in advance of the centre. Both species are similarly sculptured with fine concentric lamellae, and there is probably not much difference in the ligamentary fossette. The freshest valve procured is thin, glassy, and subtransparent, and, on examination under the microscope, presents a minutely punctate surface towards the umbo, both within and without.
Length 4^ mm., height 3, approximate diameter 2^^.
Habitat. — Station 24, off Culebra Island, West Indies, in 390 fathoms, Pteropod ooze; and Station 33, off Bermuda, in 435 fathoms, coral mud.
Necera azorica, n. sp. (PI. X. figs. 7-7h).
Testa tenuis, inajquilateralis, ovata, supernc recta, vix rostrata, mediocriter couvexa, hand nitida, rugis concentricis miuutis irregularibus postice subito obliquis ornata. Margo dorsi fere rectus, antice leviter curvatus. Latus anticum breve, rotundatum, posticum longius, rostro brevissimo, impressione baud profundo ab umbone radiant! signato, terminatum. Ventris margo late arcuatus, postice ad impressionem levissime sinuatum. Umbones parvi, parum prominentes, nucleo uitente obtuso instructi, ante medium collocati. Ligamentum minutum, obliquum.
Only a single left valve is at present known of this species. It is small, thin, rather inequilateral, irregularly ovate, having the upper margin nearly straight and the posterior end only a very little beaked. It is semitransparent-white, moderately convex,
(ZOOL. CHALL. EXP. PART XXXV. — 1885.) Mm 6
42 THE VOYAGE OF H.M.S. CHALLENGER.
and sculptured with numerous concentric, very fine, and irregular wrinkles, which, in a depression that marks off the slight rostrum, turn suddenly to the right in an oblique direction. The front and lower outlines are regularly curved, the latter, how- ever, exhibiting a slight sinuation at the radiating depression. The fi'ont portion of the dorsal edge is very short, feebly excurved, the posterior, on the contrary, being long and almost rectilinear, or very slightly concave. The umbo is small, but little raised, situated considerably in front of the middle, and terminates in a minute glossy vitreous obtuse boss. The hinge-plate is thin, bearing immediately below the beak a minute oblique ligamental jiit. The interior is glossy, with only faint muscular scars.
Length 4|- mm., height 3^, presumed diameter of a complete specimen 2|.
Habitat.- — Station 78, east of the Azores, in 1000 fathoms; volcanic mud.
This species is remarkable for the smallness of the rostrum and the peculiar wrinkled character of the concentric sculpture.
NecBra circinata, Jeffreys (PL X. figs. 4-46).
Necera circinata, Jeffreys, Ann. and Mag. Nat. Hist., 1876, ser. 4, vol xviii. p. 497. Ncara circinata, Jeffreys, Proc. Zool. Soc. Lond., 1881, p. 942, pL Ixxi. fig. 6.
Habitat. — Station 73, west of the Azores, in 1000 fathoms, volcanic mud; and at Station 85, Canary Islands, in 1125 fathoms, volcanic mud (Challenger). Other localities which I give on the authority of Dr. Jeffreys, all north Atlantic, lat. 56° 11' N., long. 37° 41' W., in 1450 fathoms ; off the west of Ireland, lat. .56° 7' N., long. 14° 19' W., in 630 fathoms ; west of Portugal, lat. 39° 55' N., long. 9° 56' W., in 994 fathoms ; Bay of Biscay.
The figure in the Proc. Zool. Soc. gives a fair idea of the Challenger specimens, but certainly exhibits a too sudden contraction of the rostrum, consequently the sinus in the ventral outline becomes too deep. The upper angle is not sufficiently sharp, and the position of the umbones is too forward, being in the shells before me (when viewed in the same position as the figure) exactly midway between the extremities. If these specimens had not been examined by Dr. Gwyn Jeffreys, and pronounced to belong to this species, I should almost have felt warranted in separating them specifically, for besides the differences already alluded to, there are other points in which they do not agree with the description in the Annals. There no mention is made of the position of the beaks, the shell is described as " rather solid," and as having " about twenty-five fine concentric and equidistant lamellar ridges or strise in the middle of the shell, which become compressed in front and disappear at the sides." The Challenger shells certainly are not " rather solid," but may be so in comparison with certain other species, and the concentric lamellae, in a specimen of the same size as that figured by Jeffreys, are considerably more numerous, there being as many as forty. Another feature which is not referred to by
REPORT ON THE LAMELLIBRANCHIATA. 43
Jeffreys is the presence of a rather strongly marked impressed ray within the valves, extending obliquely from beneath the umboues down the anterior side.
Necera obesa, Loven.
I^ecB-ra obesa, Lovdn, Ofversigt k. Vetensk.-Akad. Forhandl., 1840, p. 202, Xo. 326. Necera obesa, Sars, Moll. Arct. Xorv., p. 86, pi. vi. figs. 4a-c. Netera pelliicida, Stimpson, Invert. Grand Manan, p. 21, pi. i. fig. 13.
Habitat. — Station 78, off San Miguel, Azores, at a depth of 1000 fathoms, volcanic mud (Challenger) ; West Norway, in 40 to 650 fathoms (Sars) ; Eastern North America (Verrill); off* Long Island, in 40 fathoms (Stimpson). Atlantic Ocean, lat. 47° 38' N., long. 12° 8' W., 2435 fathoms (Jeffreys, "Porcupine" Exped., 1869); also Stations 1 and 3 of the 1870 Expedition; lat. 48° 38' N., long. 10° 15' AV., 567 fathoms; lat. 48° 31' N., long. 10° 3' W., 690 fathoms.
A single small right valve from the above Station, only 5 mm. in length, is all that was obtained of this species. In form and sculpture it corresponds precisely with the above quoted figure of Sars.
Necsra meridionalis, n. sp. (PL IX. figs. 6-66).
Testa fragilis, tenuissima, alba, concentrice subrugose striata, epidermide tenui induta, paulo in^quilateralis, alta, antice late rotundata, postice breviter lateque rostrata. Valvae fere asquales, subtumidaa, sinistra sulco hand profundo ab umbone radianti prope extremitatem posticam sculpta. Margo dorsi anticus brevis, primo parum obliquus, aliquanto arcuatus, posticus horizontalis, fere rectus ; margo inferior late curvatus, antice subito ascendens, posterius oblique surrectus, leviter sinuatus. Fossa ligamenti minima, obliqua. Pagina interna nitida, radiatim substriata, dense minuteque granulata.
This is a broadly rostrate species, excessively thin, high, tumid, broadly rounded in front and somewhat obtusely wedge-shaped behind. It is white, covered with a very thin epidermis, and exhibits distinct lines of growth and a shallow groove in the left valve, radiating from the apex to the margin near the hinder extremity, there being only the faintest indication of a similar furrow in the opposite valve. The dorsal margins are very unequal. The anterior is short, faintly excurved at first, then arcuate and suddenly descending, forming with the upcurved lower margin a broadly rounded extremity. The posterior margin is much longer, almost horizontal and straight, and the ventral outline is widely arcuate, except behind, where it rises with a faint incurvation in an oblique dii-ection. The umbones are rather large and tumid. The cartilage-pit is very small, inclined towards the posterior end, and the lateral lamellar tooth of the right valve is elongate. The internal surface of the valves is somewhat 2;lossr, exhibits a sort of close radiating substriation, and, under the microscope, appears to be minutely granular.
44 THE VOYAGE OF H.M.S. CHALLENGER.
Length 17^ mm., height 11, diameter 7^.
Habitat. — Station 157, in the Southern Ocean south-west of Australia, at a dejith of 1950 fathoms; Diatom ooze.
This species is peculiarly broadly beaked, rather swollen, and excessively thin. Since this description was written the uni<|ue specimen has been accidentally smashed, only the crushed fragments remaining. It is, however, probably capable of partial repair, and it is fortunate that it had already left the artist's hands before it was destroyed.
Necera Jilocarinata, n. sp. (PI. X. figs. 5-56).
Testa elongata, antice globosa, ]50stice subanguste rostrata, tenuissima, albida, hand nitida, lineis regularibus elevatis concentricis rostrum versus corrugatis sculpta. Margo dorsi anticus declivis, parum arcuatus, posticus paulo concavus, obliquus ; margo inferior curvatus, postice ad rostrum leviter sinuatus. Rostrum rotunde truncatum, carina filiformi radianti arcuata dimidiatum, et carina alia prope marginem dorsalem instructum, striis transversis corrugatus liueisque paucis radiantibus inconspicuis insculptum. Umbones parvi, parum producti, paulo antemediani. Valva sinistra omnino edentula, dextra dente unico laterali tenui vitrinque instructa. Ligamentum parvum, obliquum.
This is a very thin species, rather globular, with the exception of the posterior rostrated portion. It is somewhat inequilateral, whitish, wdthout gloss, sculptured with very fine and rather regular concentric elevated lines which become more or less indistinct and wrinkled in the faint dt'pression marking ofl' the rostrum. The front dorsal margin is very faintly excurvcd and rather sloping, the hinder, on the contrary, being a little concave, longer, and also oblique. The ventral is broadly excurved in front and at the middle, but has a shallow siuuatiou at the depression towards the commencement of the rostrum. This is roundly truncated at the end, and is divided by a distinct, slightly arcuate, thread-like ridge, which radiates from the beak to the lower extremity. It also exhibits a similar but rather more slender keel close under the upper margin. It is sculptured by wrinkled cross hnes of gro"wi;h, and bears in addition a few inconspicuous radiating lines. The umbones are not much elevated above the hinge-line, small, inclined towards the front, glossy at the tip, and situated rather in advance of the centre. The left valve is altogether toothless. The right has a single lamellar tooth on each side, the anterior being a trifle nearer the apex than the posterior, which, however, is the larger of the two. The ligament is small and inclined posteriorly. The interior is shining and concentrically streaked with opaque white upon a subpellucid white ground.
Length 9^- mm., height 5f, diameter 5.
Ilahitat. — Station 98, off West Africa, in 1750 fathoms; Globigerina ooze.
EEPORT ON THE LAMELLIBRANCHIATA. 45
Necera capensis, n. sp. {PI. IX. figs. 5-56).
Testa tenuis, ovato-rostrata, iiifequilateralis, albida, epidermide tenuissima induta, iiicrementi lineis striata, latere uutico subacute rotundato, postico anguste rostrato, rostro circiter ^ longitudinis sequante. Margo dorsi anticus valde declivis, leviter convexus, posticus longior, minus obliquus, concavus. Ventris margo regulariter arcuatus, postice ad rostrum sinuatus. Umbones pauIo postmediani, leviter supra marginera elevati.
Like most species of Necera this is very thin and fragile. It has a rather long beak behind, is somewhat acutely rounded in front, rather angular at the apex, and well curved below. It is inequilateral owing to the length of the rostrate end, whitish, and covered, more or less, with a thin but rougliish epidermis, which is less worn off the beak than elsewhere. The front dorsal outline is slightly convex and considerably sloping, the posterior being somewhat longer, less oblique, and gently concave. The sculpture consists of fine concentric lines of growth, most conspicuous upon the beaks. The <-artilage-pit is small, the lamellar lateral tooth of the right valve moderately long and erect, and the scars and pallial line very indistinct.
Length 15 mm., height 8, diameter 5.
Habitat. — Station 142, off the Cape of Good Hope, at a depth of 150 fathoms ; green sand.
This, like several other species of the genus, is principally distinguished by its shape, there being little of importance as regards sculpture, epidermis, and hinge to separate it from certain allied forms. It differs from Netera rostrata, Spengler, in possessing a shorter beak, and the ventral margin in front of the rostrum is longer and less arcuate. In outline it more closely resembles Nccera hindsiana, A. Adams, from Japan, but differs from it in having finer concentric sculpture and a more acute anterior end.
Necera j^lciten.sis, n. sp. (PI. IX. figs. 4-46).
Testa tenuis, albida, elongata, antice acute rotundata, postice sublonge rostrata, mediocriter globosa, incrementi lineis striata, hand nitida. Margo dorsi anticus primo rectiusculus, deinde obliquus, parum arcuatus, posticus elongatus, paulo declivis, subrecti- linearis vel leviter concavus. Margo inferior late arcuatus, postice sub rostro sensim sinuatus. Umbones leviusculi parum prominentes, paulo ante medium collocati. Rostrum impressione radianti definitum, subabrupte truncatum. Valva dextra dente laterali lamcUiforuie postico instructa. Fossa ligamenti valvte sinistra^ minuta, paulo obliqua. Linea cardinis ante umbones leviter expansa.
This species is very thin, ovate-rostrate, moderately convex, sharply rounded in front, and ends behind in a rather long but not very slender beak. It is white, without
46 THE VOYAGE OF H.M.S. CHALLENGER.
lustre, and sculptured with fine lines of growth. The valves exhibit a broad shallow depression, radiating from the umboues and marking ofi' the rostrum. This is rather abruptly truncate at the end, and faintly ridged from the beak to the lower corner, with the lines of growth rather strongly developed. In the left valve there is a second slight ridge, very close to the upper margin, marking off a linear dorsal area. The front dorsal margin rises a little, close to the umbo, then descends obliquely with only a very slight curve. The j^osterior margin is longer, slopes but very little, and is the least concave. The ventral outline forms under the main portion of the shell a regular broad curve, but at the termination of the radiating depression is gently sinuated. The umbones are only a little elevated, and somewhat in advance of the centre. The left valve is toothless, but possesses a minute and slightly oblique cartilage-pit just under the apex. The right valve has a single slender elongate lamellar tooth on the posterior side, and the hinge-line in both valves in front is a little expanded. The muscular impressions are very feebly indicated.
Length 13 mm., height 7, diameter 5.
Habitat. — Station 320, otf the mouth of the Eio de la Plata, in 600 fathoms ; green sand.
In form this species resembles to some extent Necera ohesa, Loven, and Necera Umatilla, Dall. It is less convex than the former, is more sharply rounded in front, and has less prominent umbones, the latter being more strongly sculptured.
Necera herguelenensis, n. sp. (PI. XXIV. tigs. 8-8/*).
Testa parva, subglobosa, postice bi'eviter rostrata, concentrice lirata, liris tenuibus valde elevatis, sujara rostrum flexuosis, ad liram obliquam medianam obsoletis. Margo dorsi anticus rectiusculus, declivis, posticus paulo concavus, minus obliquus. Margo inferior antice et in medio late curvatus, sub rostro distincte sinuatus. Umbones parvi, circa in medio, ad cacumina leves. Valva dextra dente unico valido submarginali pone umbonem munita, valva sinistra contra edentida.
This little shell is rather globose, nearly equilateral, rounded in front, much contracted and beaked behind. It is white, and ornamented with about twenty, fine, much elevated, concentric, lamelliform Yivsd, which are attenuated and flexuous in a depression or con- striction marking off the rostrate end, and almost terminate at a slight keel which runs from the umbones to the lower corner of the curved truncate beak. Above this carina there is a second finer one, but nearer to the dorsal edge. The front dorsal margin is somewhat oblique, but not much curved, the posterior being rather concave. The ventral outline is distinctly sinuate under the rostrate end, and greatly arcuate at the lower part and in front. The umbones are small, nearly central, and smooth at the tips. The hinge is composed of a single strongish tooth in the right valve, situated within the dorsal margin just behind the umbo.
JIEPORT ON THE LAMELLIBKANCHIATA. 47
Length 4 J mm., height 3, dinmetcr 2|.
Habitat. — Off Christmas Harbour, Kerguclen IsLand, in 120 fathoms.
A pretty little species, remarkable for its elevated thin lamelliform lirse.
Necera angasi, n. sp. (PI. IX. figs. 2-26).
Testa NecBrcB rostratce similis, sed margine dorsi antico magis obliquo, rectiusculo, margine ventrali postice minus subito contracto, denteque laterali posteriori valv£e dextrse graciliori.
Length 9^ mm., height 5, diameter 3^.
Habitat. — Station 164b, off the coast of New South Wales, in 410 fathoms; green mud.
This species is so very like Nea'ra rostrata of Spengler, that to give a detailed description of it becomes unnecessary. It docs, however, differ a little in form, the hinder dorsal slopes being almost rectilinear and a trifle more oblicpie. There is a difference also in the lower margin, the contraction at the commencement of the rostrum being less sudden, and the anterior end is rather more acute. The sculpture in both forms is of the same character, although that in the Australian shell is perhaps somewhat more delicate. The present species has also a smaller and more slender hinder lateral tooth in the right valve. I have much pleasure in naming this species after my friend G. F. Angas, Esq., who lias written several important papers on the Molluscan fauna of Australia.
Since the above description was written the only specimen obtained has been accidentally smashed, but fortunately after leaving the artist's hands.
Necera elegans, Hinds.
Nerera elegans, Hinds, Proc. Zool. Soc. Loud., 1843, p. 7G.
Necera elegans, A. Adams, Ann. and Mag. Xat. Hist., 1864, vol. xiii. p. 206.
Necera moluceana, Adams and Eeeve, Zool. Voy. Samarang, ]\Iollusca, p. 84, pi. xxiii. fig. 4.
Habitat. — Station 189, Arafura Sea, south-west of New Guinea, in 25 fathoms, green mud (Challenger) ; New Guinea, China Sea, and Singapore, on a muddy floor, in from 7 to 18 fathoms (Hinds); Molucca Islands, Gillolo (Adams and Reeve); Mine Sima, Japan, in 63 fathoms (A. Adams).
I fuUy concur Tvith Adams and Tryon ' in considering the Necera, rtwluccana synony- mous with this species. It is a form easily recognised by the peculiarity of its oblique sculpture. It is rather convex, thin, not glossy, covered more or less with a very thin pale epidermis, sharply rounded in front, contracted and narrowly rostrate behind. The ventral outline is regularly widely arcuate under the main portion of the shell, with a sudden sinuation at the commencement at the beak. The anterior dorsal margin is
' Amir. Journ. Conch., vol. iv., Appendi.x, p. 97.
48 THE VOYAGE OF H.M.S. CHALLENGER.
faintly curved and rather oblique, the posterior, which is somewhat longer, being, on the contrary, considerably concave. The valves are all but equal, and sculptured with numerous oblique, wavy, slender ridges, which almost disappear in front, leaving a com- paratively smooth lunular space, and vanish posteriorly at a fine radiating keel which bisects the rostrum. The latter bears nearer the dorsal edge a second carina, which, being slightly curved, marks oS' a smooth narrow dorsal area, the space between the ridges being, on the contrary, marked with rather rough transverse lines of growth, these on the rest of the valve, being concentric, cut across the oblique riblets. The cartilage-process is small, short, and inclined slightly posteriorly. The right valve has a thin elongate hinder lateral tooth.
NecBra sp.
Habitat. — Station 23, ofi' Sombrero Island, West Indies, iu 450 fathoms ; Pteropod ooze.
Only the umbonal portion of a right valve was obtained, wliicli, on account of its large size, may be wortli recording. It indicates a species of as large size as Netera chinensis, Gray, and equally solid. It evidently has a long slender rostrum, and is sculptured like Necera rostrata, Spengler. It has a trigonal cartilage-pit having the lower margin rounded and placed almost perpendicularly under the tip of the beak. There is a very strong short erect hinder lateral tooth, immediately beneath which is a very deep muscular scar.
NecBra sp.
Habitat. — Station 24, oil' Culebra Island, West Indies, in 390 fathoms; Pteropod ooze.
A single left valve from the above Station is apparently distinct from all the numerous known species of this genus. It is very thin, probably young, pellucid, moderately convex, shortly rostrate, glossy, and sculptured with fine lines of growth towards the lower outline. The hinge-line is almost horizontal, very slightly excurved anteriorly, and very feebly concave behind. The anterior end is broadly rounded, and joins the dorsal margin with a rounded angle. The lower outline is well curved, rising considerably at the posterior end, Avhere it is also shallowly sinuated. The Ijeak, di\ided by a slight ridge radiating from the umbo to the lower corner, exhibits one or two other very faint raised radiating lines, and is rather abruptly truncated. The umbo is small, .shining, only a little elevated, and placed a trifle in front of the centre. The cartilage-j)it is very small, oblique, and just under the apex.
Having but a single valve for examination, and that probably immature, it would be unwise to name it specifically; however, the record of its existence may possess some value.
REPORT ON THE LAMELLIBRANCHIATA. 49
Section B.
Necera curta, Jeffre3-s.
Necera curta, Jeffreys, Ann. and Mag. Kat. Hist., 1876, .ser. 4, vol. xviii. p. 495. Necera curta, Jeffreys, Troc. Zuol. Soo. Loud., 1881, p. 943, pi. Ix.xi. fi;.;. 10.
Habitat. — Station 75, oft' the Azores, in 450 fathoms ; volcanic mud ; also Station" 33, oft" Bermuda, in 435 fathoms ; other localities given by Jeffreys are Stations 16 and 17, lat. 39° 55' N., long. 9° 56' AV., 994 fathoms; lat. 39° 42' N., long. 9° 43' W., 1095 fathoms ; and 24 to 28a of the "Porcupine" Expedition, 1870.
A single left valve from Station 33, measuring 9| mm. in length and 6^ in height, agrees very closely with the figure cited aljove. This, too, is the specimen referred to b}^ Jeffreys in the Proc. Zool. Soc. Lond. {loc. cit.). It exhibits one slight difference, namely, in lacking the radiating striae on the anterior side. I think it likely that this may be the same species as that referred Ijy Dall to Necera costellata (var. corpidenta)}
A perfect shell containing the animal, from Station 75, shows that the right valve is rather smaller than the left, the ventral margin of which projects slightly beyond the other.
Necera fallax, n. sp. (PI. X. figs, -l-'lh).
Testa tenuissima, giobosa, antice acute rotundata, postice breviter ro.strata, incre- menti lineis striata, liris radiantibus teuuibus postice instructa. Margo dorsi anticus arcuatus, valde declivis, j^osticus paulo concavus, obliquus. Margo inferior late curvatus, postice leviter sinuatus et crenulatus. Umbones leves, paulo post medium collocati. Dens lateralis posticus valvse dextrse elongatus, uscj[ue ad rostrum productus. Pagina interna subnitida, postice radiatim subsulcata.
This species is rather globose, somewhat inequilateral, thin, narrowed to a sharply rounded end in front, contracted and shortly beaked behind. It is .smooth towards the umbones, sculptured elsewhere by fine lines of growth, and ornamented upon the hinder half of the valves with aljout sixteen fine radiating lirae, of which those upon the beaked extremity are the finest. The anterior dorsal outline is rather longer than the posterior, much sloping and excurved, the hinder, on the contrary, being obliquely con- cave. The ventral margin is broadly arcuate, with the exception of a faint sinuation at the rostrum, where it is somewhat crenulated. The l)eaks are smooth, only slightly prominent, and to the naked eye appear to have a posterior inclination, but in reality are turned at the apex towards the front. The hinder lateral tooth of tlie right valve is rather long, extending to the commencement of the narrowed extremity. The interior
' Vide Bull. Mus. Comp. Zool., vol. ix., Xo. 2, p. 110. (zOOL. CHALl,. EXP. PART XXXV. 188-5.) Mill 7
50 THE VOYAGE OF H.M.S. CHALLENGER.
of the valves is sliallowly radiately grooved towards the posterior end, and exhibits a moderately strong supporting ridge beneath the iimlio.
Length 7 mm., height 5, diameter 3;^.
Habitat. — ^Station 185b, east of Cape York, in 155 fathoms ; coral sand.
Section E.
NecBva teres, JefFre5-s (PI. X. figs. 3-3&).
Xewra teres, Jeffreys, Proc. Zool. Soc. Lond., 1881, p. 939, pi. Ixxi. fig. 2.
Testa tenuis, semipellucido-albida, serica, giobosa, rotundato-triangularis, postice breviter rostrata, sequivalvis, sequilateralis, ad extremitatem posticam hians. Margo dorsi anticus declivis, vix excurvus, posticus oblic^uus, concavus. Ventris margo late arcuatus, prope rostrum leviter sinuatus. Valvse concentrice tenuiter striatge, carina obliqua, filiforme, radianti, I'ostrum dissecante, ad iustructae, liriscjue paucis aliis teuuibus radiantibus inter carinam et marginem dorsi ornata3. Umbones nitidi, mediocriter elevati, mediani, apicibus antice versis. Denies cardinales nuUi. Laterales duo in valva dextra breves, lamelliformes, valde prominentes. Ligamentum obliquum, latus posterius versus incliuatum, in loculamento insigne, postice acuminato, in. valva .sinistra situm. Paoina interna nitida, radiatim striata. Cicatrix anterior parva, postica major, porca rotundata valida intus marginata.
This species is rather globose, triangularly rounded, shortly beaked, and gaping behind, thin, semitransparent-white, and exhiliits towards the lower outline, and upon the rostrum, more or less of a thin fibrous epidermis. The valves are equal and have a silky appearance, being sculptured with fine strias of growth. The beaked portion terminates in a short curved truncation, and is divided down the middle by an oblique, slightly arcuate thread-like carina, extending from the umbo to the lower end of the rostrum. Between this keel and the dorsal margin, the surface is ornamented with a fewer, finer, and less conspicuous radiating lirse, which are crossed by rougher lines of growth than those upon the rest of the shell. The dorsal margin is moderately oblique on both sides, being nearly rectilinear in front, and gently concave behind. The anterior end and ventral outlines are regularly curved, but the latter, behind, under the rostrum, is just faintly incurved or sinuated. The umbones are fairly raised, glossy at the tips, which are curved over towards the front and situated midway between the extremities of the shell. The right valve has a very prominent lamellar lateral tooth on each side rather near to the apex, the posterior, after being suddenly truncate behind, is continued in the form of a slightly elevated ridge, immediately under the dorsal margin, some distance along the rostrum. There are no cardinal teeth in either valve. The left valve has the margin thickened on both sides, especially in front of the umbo, near
REPOET ON THE LAMELLIBRANCHIATA. , 51
which there is a peculiar pit for the reception of the anterior lateral tooth of the other valve. The ligament is directed obliquely backwards, and is sustained in the left valve in a small but thickish process which juts out distinct from the dorsal margin. The interior is glossy, but marked with shallow radiating grooves or striae, which are even more or less visible externally, owing to the transparency of the shell. The anterior scar is small, the posterior rather larger, and margined on the inner side in' a strong rounded ridge descending from above, under the dorsal slope.
Length 10 mm., height 7, diameter 4f.
Habitat. — Station VIII., oil' Gomera, Canary Islands, in 620 fathoms ; \olcanic mud.
The shells here described have been referred by Jeffreys ^ to his Necera infiata, which, however, upon examination, proves quite distinct. The form of that species is somewhat difi'erent, the right valve possesses " a small upright triangular cardinal " tooth, and there is "a long laminar lateral on the posterior side " in the left, both of which are wanting in these specimens, which differ also in lieiug radiately lii-atc upon the rostrum and in some of the hinge-characters. Smce writing the above description, I have had an opportunity of examining the type of this species, and find that these Challenger specimens are undoubtedly conspecific.
Section F.
Nemra hrazieri, n. sp. (PI. IX. figs. 3—36).
Nemra {Rlunomya) rugata, Angas («o« A. Adams), Proc. Zool. Soc. Lund., 1867, p. 914.
Testa parva, elongata, sublonge rostrata, iusequilateralis, mediocriter convexa, alba, lamellis tenuissimis coucentricis, supra rostrum coarctatis minusque elevatis instructa. Margo dorsi anticus valde declivis, leviter arcuatus, posticus concavus, elongatus. Margo inferior antice et in medio arcuatus, postice baud profuude sinuatus. Eostnim augustum, rotunde truncatum, bicarinatum, valvse relicpio impressione levi notatum. Umboues parvi, subconici, vix involuti, antemediani. Dentes laterales valvse dextrse breves, valde erecti, prope apicem coUocati. Yalva sinistra tul)erculo dentiformi, paulo ante apicem mimita.
The shell of this species is small, rounded in front, and terminates posteriorly in a moderately long and narrow beak. It is not very convex, rather inequilateral, white, and not glossy. The valves are somewhat unequal in size ; the right is the smaller, of a narrower appearance, and falls within the ventral margin of the left when the valves are closed. They are marked posteriorly with a broad shallow depression radiating from the uml)o to the ventral margin, and marking off the rostrum. The sculpture consists of from twenty to thirty slender concentric lamellae, which become crowded and less erect towards the depression, and upon the beak. This exhibits a faint
> rnc. Zool Soc. Loud., ISS], ].. 94-2.
52 . THE VOYAGE OF H.M.S. CHALLENGER.
ridge down the middle from the apex to the lower extremity, and a more distinct keel nearer the dorsal mari,nn, marking oft' a smooth upper area. The front dorsal margin is veiy oblique, somewhat curved, and shorter than the jjosterior, which is less sloping and rather concave. The ventral outline is widely arcuate in front and at the middle, but shallowly sinuate at the depression. The umbones are small, only slightly raised above the hinge-line, hardly incurved, and, at the extreme tip, do not appear to incline either anteriorly or posteriorly, although, when the valves are viewed externally, they curve over towards the hinder .side. The right valve has a short Imt very erect lamellar lateral tooth on each side near the umbo, the posterior, however, is prolonged under the dorsal margin, in the form of a ridge, some distance along the rostrum. It also has, just in front of the apex, a small triangular dentiform projection of the dorsal margin. The left valve has no lateral, but a single thickish tubercular denticle, just in front of the apex. The ligament is small, oblique, and posteriorly inclined, not in a prominent process, but attached to the inner surface of the shell. The interior is glossy, exhibiting more or less of the external concentric ribbing, especially in the right valve. The muscular impressions are indistinct.
Length 6 mm., height 3f, diameter 2.
Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms (Challenger) ; Moreton Bay (British Museum).
Section K.
Necera clavicidata, Dall (PI. IX. figs. 8—8/').
Necnra daviailala, Dall, Hull. Mus. Comp. Zoul., vol. ix., Xo. 2. p. 11 2. Habitat. — Station 33, oft" Bermuda, in 435 fathoms ; coral mud.
None of the Challenger specimens are as large as that descriljed by Dall from Station 44 of the " Blake " Expedition, the largest being only 6 mm. in length. The right valve has a singular acute (almost hooked) denticle just in front of the apex, the left l^eing entirely without teeth. The great feature of this species is the peculiar shelf- like expansion within the posterior dorsal margin, the special use of which is at present a matter of conjecture. It may be for the reception of the hinder adductor muscle, although I am inclined to believe such is not the case.
Necera congenita, n. sp. (PL X. figs. 1-1/*).
Testa NecercB davicidatw similis, sed angustior, minus convexa, postice latius rostrata, margine dorsi postico rectiusculo, ventrali postice vix sinuato, clavicula interna magis elongata, et ligamenti fossa angustiori instructa.
REPORT ON THE LAMELLIBRANCHIATA. 53
This species, on accoimt of the internal wlielf-like process l)eueatli tlie posterior dorsal margin, is <;loseIy related to Xewra daviculata of Dall, and may best be recognised by a comparative description. It is less globose than that sjjecics, a little narrower, more broadly rostrate behind, the ventral margin being regularly (mrved, and without a shallow posterior sinuation, and the dorsal outline, behind the beak, scarcely at all incurved. The umbones are placed more forward than in Xeaixi daviculata, and do not curve over so much towards the posterior end. Within I find two differences. In the fir.st place the " clavicle " is longer, and commences at the upjier end under the dorsal margin, whilst in Ball's species the inner margin of the clavicle is joined al)0ve to the process which receives the internal hinge-cartilage. The second distinction consists in the narrower character of this process, which also is almost parallel witli the hinder dorsal edge, whilst in Necera daviculata it juts farther out into the shell.
Length 4 mm., height 2f, presumed diameter 2^.
Ilahitat. — Station 33, otf Bermuda, in 435 fathoms ; coral mud.
Only a single left valve is. at present known of this species, and that probal)ly not full grown. Were there no other diflerence except that of form I should have hesitated to have separated it from Necera daviculata ; seeing, however, that the clavi('le and hinge are also dissimilar, I have no doubt of this being a distinct species. It is unfortunate that no right valve is at hand for examination, for most likely a modification of the peculiar sul)hooked tooth, met with in the allied form, would occur in this species. I am exceedingly sorry to have to record the complete destrviction, through the (;arelessness of a servant, of this particularly interesting valve since it was returned to me by the artist.
Section M. Necera frag ilissima, n. sp. (PI. IX. figs. l-l/>).
Testa magna, tenuissima, ovata, postice Ijreviter rostrata, globosa, hand nitida, alba, ina3i|uilateralis, liris radiantiljus tenuibus instructa, incremeutique lineis striata, ^largo dorsi auticus altus, supra umbones productus, posticus paulo excavatus. Latus anticum superne obliquum, parum arcuatum, ad extremitatem subacute rotundatum. 3Iargo ventralis late curvatus, postice sub rostro leviter sinuatus. Rostrum breve, liris radiantibus obsoletis ornatum, superne pone umbones aream angustam impressam exhibens. Umbones postmediani, ad apicem acuti, paulo supra marginem product!. Yalva dextra postice vix dentata. Pagina interna parum nitida, radiatim sulcata et striata.
This species is excessively fivagile, rather large and inflated, inequilateral, ovate- rostrate, not glossy exteriorly, white, and sculptured with numerous fine radiating
u4 THE VOYAGE OF II.M.S. CllALLEJS'UElt.
ridges, of which those upon tlie surfece between tlio middle of tlic valves and the commencement of the rostrum are thicker than the rest, those upon the beak itself beiiio- almost obsolete. In addition, it is ornamented with the lines of (irowtli, which, in some places, are so strong as to produce a slightly cancellated appearance. The front dorsal margin is much elongated and a little curved, the posterior, on the contrar)-, being slightly concave and just a trifle oblique. The anterior end is obliquely sloped above, with a very small curve, and terminates in a moderately sharply rounded extremity. The ventral outline forms a broad curve except beneath the rostrated end, where it is feebly sinuated. The beak is broad, rather short, curvedly truncate at the end, and exhibits above, a narrow, slightly sunken dorsal area. The umbones nie moderately large and acute, recurved, somewhat raised above the hinge-line, and located rather in advance of the centre. The hinire mioht be said to l)e toothless, although in the right valve there is a very insignificant ridge, starting from the ligament-pit and continued a little way parallel witli the posterior dorsal margin, M'hich might be regarded as an incipient lateral tooth. The ligament is small, short, and oblique, inclining towards the anterior end. The interior is not very glossy, but exhibits radiating grooves and striae corres2:)on(ling to the external ridges and lira;. The hinder muscular scar is more distinct than the front one, ami Imiilei'ed anteriorly by a thickened ridge.
Length 20 mm., height 12, diameter 9.
Habitat. — Off Prince Edward Island, in 300 fathoms.
This is a large and very fragile species, in many respects similar to Neara ciuia. Jefireys. It is perhaps a little longer in proportion to the height, has more distinct lii-se on the anterior half of the surface, a narrow sunken dorsal area, and lacks the *' short strong triangular lateral " tooth on the posteiior side of the ri-ht Aahc wliicli occurs in that species.
Puroiiii/a, Forbes.
Poromya australis, u. sp. (PI. XI. figs. 2—26).
Testa parva, aequilateralis, tenuis, albida ; margo dorsi utrinquc valdc declivis, antice concaviusculus, postice Icviter convexus. Valva dextra mediocriter convexa, in regione lunulari concave depressa, prope marginem dorsalem posticum carinata, undique granulata, granulis confertis, erectis, in quincuncibus digestis. Umbo prominens, ad apicem levigatus, antrorsum versus. Dens cardinalis unicus validus, erectus, infra apicem locatus. Pagina interna alba, nitida, leviter margaritacca.
Only a single right valve of this species was obtained. It is al)out as long as high, rounded at both ends, and along the ventral margin it is more gentl}' curved. It is
REPORT ON THE LAMELLIBRANCHIATA. 55
tliininsh, equilateral, morlevately convex, white, and ornamented with innumerable minute elevated granules arranged in (|uincuncial foshiou. The dorsal margin is considerablj' ol)li(|ue on both sides of the ])rominent beak which is well curved over towards the iVoiit, and sniDOtli and glossy at the tip, in front of wliicli there is a lunular depression, which is not, however, defined by a line. The anterior dorsal slope is a trifle concave, the posterior side, on the contrary, l)eing slightly convex, exhibiting a sharpish keel or ridge very close to the edge, marking oft" a linear dorsal area. The single cardinal tooth is large, strong, erect, and situated immediately beneath the apex of the umbo. The interior of the valve is whitish and somewhat pearl)^.
Length 4|- mm., height 4^, diameter of valve 1|^.
Habitat. — Station 185b, east <jf Cape York, North Australia, in 155 fathoms ; coral sand.
This is a shorter shell than the European Povomija granidata of Nyst, with more sloping dorsal margins and a more c-urved ventral outline. It is also more coarsely granulated, and the pit containing the internal ligament is smaller and more equUater- ally triangular.
Povoiiiija Iwvis, n. sp. (I'l. XI. tigs. 3—36).
Testa insequilateralis, ovata, antice pauIo acuminata, postice latior, leviter sub- truncata, alba, tenuis, nitida, incrementi lineis levibus striata, undicj^ue microscopice subpunctata. JMargo dorsi utrinque declivis, postice subrectUinearis, antice leviter excurvatus, prope umbonem contractus, lunulam parvam concavam formans. Margo ventris late arcuatus. Umbones parvi-, paulo supra marginem dorsalem producti, alic|uanto post medium siti. ^"idva. dextra dente unico subvaUdo infra umbonem instructa, lineaque cardinis anti(;e profunde sulcata. Proxime sub margine dorsali pone umbonem est liganienti sulcus parvus hand })rofundus. Pagina interna nitida, sul)- margaritacea, ladiatim substriata.
Of this species only tluee right valves are at present known. It is of an ovate form, a little acuminate in front, broader and somewhat truncated behind. It is not very convex, rather inecj^uilateral, the anterior side being the longer. It is thinnish, white, glossy, sculptured with very fine lines of growth, and everyA\'here exhibits a micro- scopic shagreened surface, only \asible under a compound lens. The front dorsal margin is a little curved and sloping, the posterior being shorter, straighter, and more oblic[ue, and turned at right angles to the rest of the valve, forming a narrow dorsal area. The ventral outline is regularly and widely arcuate, ascending equally at both ends. The l>eaks are small, slightly raised aljove the hinge-line, are situated behind the centre, and curve towards the front over a small concave lunule. The interior is glossy, semipearly, and finely radiately substriated, especially towards the lower margin. There
56 THE VOYAGE OF 11. M.S. CHALLENGER.
t is a single strongish tootli in the right valve just Lenoath the uml>o, with a large deep triangular excavation behind it, the hinge-plate being rather deeply grooved on the anterior side. Immediately under the dorsal margin, a little behind the beak and above the triangular excavation mentioned above, there is a small shallow elongate pit, no doubt for the reception of a small internal ligament. The muscular impressions are indistinct.
Length 7 nnn., height b\, presumed diameter of a perfect specimen 4.
Habitat. — Station 185b, east of Cape York, North Australia, in 155 fathoms; coral sand.
Although not minutely granulated like the typical forms of Poromija, still, in the composition of the hinge, this species, so far as one can judge from right valves only, accords with that genus. The interior has a similar semipearly character, and is radiately substriated, so that the location is probablj' correct.
Subfamily Myin^.
Mya, Linne. Mj/a sp.
Habitat. — Flinders Passage, Torres Strait, in 7 fathoms.
Only a minute left valve of a species of Mya was obtained at this locality. It is not unlike Mya japonica in outline, and possibly it may be the young of that form. As no species of the genus has been recorded from this district, its occurrence may be worthy of mention.
Family M a c t r i d .e.
Subfamily Lutrariin.e.
Pacta, Gray.
«> Raeta pulcheUa, (Adams and Reeve).
Poromi/a piildiella, Adams and Reeve, Zool. Voy. Samarang, p. 83, pi. xxiii. fig. 1. Raeta 2Julchel.la, H. and A. Adams, Gen. Moll., vol. ii. p. 386. Madra ronfralis, De.shayes, Proc. Zool. Soc. Lond., 1854, p. 69. Mudra rostralU, Reeve, Con. Icon., vol. viii. pi. xxi. fig. 119.
Habitat. — Off Yokohama, in 8 to 14 fathoms ; and Station 233c, off Japan, in 12 fathoms.
This species was originally described from specimens dredged off the shores of Borneo, and again as Mactra rostralis, from Japanese examples. It is more elongate than the young of the American Pacta canaliculata, and somewhat more equilateral.
REPORT ON THE LAMELLIBRANCHIATA. 57
Subfamily Mactrin.e. Mactra, Linue.
Mactra {Mactrinula) pUcataria, LiiiiR'.
Mactra iMcataria, Linne, Syst. Nat., ed. 12, p. 1125.
Mactra pUcataria, Chemnitz, Conch. -Cab., vol. vi. p. 213, pi. x.x. figs. 202-204.
Mactra plicataria, Reeve, Con. Icon., vol. viii. fig. 26.
Mactra {Mactrinula) jilicataria, Kobelt, Illust. Conch., p. 324, pi. xciii. fig. 8.
Mactrinula pUcataria, H. and A. Adams, Genera, vol. iii. pi. xcix. figs. 2, 2a.
Mactrinula plicataria, Chenu, Manuel Conch., vol. ii. p. 55, fig. 226.
Habitat. — Cape York, North Australia, in 3 to 12 fathoms (Challenger); Java (Linn.); Sumatra (Reeve); Tranquebar (Chemnitz).
Only a single small specimen about half an inch in length was obtained. This is not quite typical, having the concentric riblets more or less obsolete, except down the anterior side, in this respect more like Mactra Uvvis, Chemnitz, which I believe is another form of this species.
Mactra [Mactrinula) de2)ressa, Reeve.
Mactra depressa (ISpengler) (teste Reeve), Skrivt. af Naturhist. Selskabet, 1799, vol. v. p. 118. Mactra depi-essa, Reeve, Conch. Icon., vol. viii. fig. 67. Mactra ovalina, Reeve (? Lamarck), Conch. Icon., fig. 66.
Habitat. — Port Jackson, in 2 to 10 fathoms (Challenger and G. F. Angas); also Port Philip (Angas and Brit. ]\Ius.).
I see no sufhcieut reason for separating the above two forms. Probably Reeve was influenced by the localities attached to the specimens in Cuming's collection. " West Columbia " I merely regard as one of the numerous geographical errors which occur throughout that collection, many of which unfortunately have found their way into print in the works of Reeve and Sowerby. Mactra angulifera, Deshayes, is scarcely sufficiently distinct to warrant its specific separation. The figure in Delessert's Recueil, pi. iii. figs. 7a, b, is a verj' cUfierently shaped shell to that represented in the Conchologia Iconica.
I have little doubt that Reeve's identification of this species with the Mactra depressa of Spengler is incorrect. It is described by the latter author as having a sulcated lunule and a liueated area (" vulva arcuata, sulcata, ano lineato "). It is also characterised as equilateral, the posterior carinse are not mentioned, and it is said to come from the coast of Guinea. The name " depressa " has been subsequently employed by Deshayes for a fossil species (Coq. foss. de Paris, vol. i. p. 32).
(ZOOL. CHALL. EXP. — PART XXXV. — 1885.) ^I HI 8
58 THE VOYAGE OF H.M.S. CHALLENGER.
Mactra incarnata, Deshayes.
Madra incarnata (Deshayes), Reeve, Conch. Icon., vol. viii. fig. 6L TrigoufUa incarnata, H. and A. Adams, Genera Rec. JIoll., vol. ii. p. 376. Tricjimalla incarnata, Tryon, Amer. Journ. Conch., vol. iii., Appendix, p. 37.
Habitat. — Station 212, .south of the Philijjjjine Mands, iu 10 fathoms; saud.
This species was described from specimens said to have been obtained at Swan River. Only six small not haLf-grown valves were collected by the Challenger at the above locality. At this age they appear rather more trigonal than when adult, and exhibit more rosy radiation in the interior of the valves. The species is closely related to Mactra eximia of Deshayes, which, however, is a somewhat higher shell, having a more strongly curved basal margin and somewhat coarser sulci on the lateral areas.
There are three or four species which are characterised with similar lateral grooving, and border rather closely on the present form. Among these may be mentioned Mactra semistriata, Deshayes, Mactra eximia (already referred to), Mactra antiquata, Spengler, and Mactra mera, Deshayes, the two last being unquestionably one and the same shell. The distinction between those and other closely allied forms of Mactra may be very trifling, still they appear fairly constant, each locality producing its variety.
Mactra isaheUeana, d'Orbigny.
Mactra isabdleana, d'Orbigny, Voy. Ainerique M^rid., vol. v. p. 509 ; Atlas, vol. ix. pi. Ixxvii.
figs. 25, 26. Mulinea isabelliana (d'Orbigny), Tryon, Amer. Journ. Conch., vol. iii.. Appendix, p. 31.
Habitat. — Station 321, off Monte Video, in 13 fathoms; mud.
D'Orbigny says that this species is found at all points near the mouth of the Eiver Plate at Maldonado, at Monte Video, and on the oj)posite coast at Cape San Antonio.
It is a moderately solid shell, a little inequilateral, somewhat trigonal, and generally more acute posteriorly than in front. It is of a whitish-brown colour, and more or less covered with a yellowish-olive epidermis. The surface of the valves is sculptured by concentric strise of gro'ni:!!, and generally exhibits, here and there, stronger grooves and elevations, which may indicate periods of arrested increase. The jjaUial sinus is subject to some variation, in some instances being deeper than in others, but it never apparently extends nearly half-way across the valves. The external ligament is minute, situated above the internal cartilage, and is separated from it by a narrow shelly partition.
REPORT ON THE LAMELLIBRANCHIATA. 59
Mactra achatina, Chemnitz.
Madra achatina, Chemnitz, Conch. -Cab., vol. xi. p. 218, pi. cc. figs. 1957, 1958. Mactra achatina, Reeve, Conch. Icon., vol. viii. pi. xii. fig. 51. Mactra maculosa, Lamarck, Anim. Sans Vert., ed. 2, vol. vi. p. 100. Mactra maculosa, Hanley, Cat. Reo. Shells, pp. 29 and 340, pi. xi. fig. 27. Mactra ornata. Gray, Ann. and Mag. Nat. Hist., 1837, vol. i. p. 371. Mactra ornata, Eeeve, loc. cit., pi. xiii. fig. 58.
Habitat. — Admiralty Islands, in 16 to 25 fathoms (Challenger) ; Philippine Islands (Reeve), Ceylon, and Nicobar Islands (Chemnitz) ; var. ornata, China (Gray) ; Ceylon (E. W. H. Holdsworth in Brit. Mus.).
Among the synonymy of this species given by Reeve and copied by Conrad (Amer. Journ. Conch., vol. iii., Appendix, p. 35) I find mentioned Mactra maculata as of Hanley. The species referred to by the latter author is not the Mactra achatina, but the true Mactra macnlata of Chemnitz, which is a very different shell. It is figured by Reeve, Conch. Icon., fig. 56, and again as Mactra reevei, Deshayes, on pi. xvi. fig. 85.
The Mactra ornata of Gray I regard as the typical form of this species, and the shell figured by Reeve (fig. 51) as a variety. Specimens in the British Museum from Ceylon, one of the localities mentioned by Chemnitz, agree better as regai'ds colour and form wdth the figure and description in the " Conchylien-Cabinet " than those from the Philippine Islands and Admiralty Islands.
Mactra incerta, n. sp. (PI. V. figs. 7— 7c).
Testa mediocriter convexa, ovato-subtrigona, paulo inaequilateralis, tenuiuscula, nitida, levigata, utrinque umbones versus radiatim sulcata, albida, radiis latis interruptis fuscis variegata. Margo dorsi anticus elongatus, oblique leviter couvexus, posticus A^alde declivis, parum arcuatus ; margo inferior late curvatus. Umbones acuti, ad apicem fuscescentes, paulo post medium collocati. Cardo albus, dentibus lateralibus gracilibus munitus. Pagina interna nitida, coloribus externis tincta. Sinus pallii mediocris, rotundata.
This little species has the anterior side rather longer than the posterior, the former being narrowed towards the end, where it is sharply rounded, and the latter broader, obliquely suljtruncate, terminating in a rounded angle at the base. It is a thinnish shell, rather glossy, with very little sculpture upon the greater portion of the surface, but rather strongly grooved laterally on both sides of the beaks. The ground-colour is whitish, copiously stained with brown in the form of broad interrupted rays which are faintly obscured by an excessively thin epidermal film. The front dorsal margin is a little convex and descends obliquely, the posterior also being slightly excurved, but much
60 THE VOYAGE OF H.M.S. CHALLENGER.
more suddenly sloping. The lower outline is very gently curved, rising rather higher in front than behind. The beaks are small, brown at the tips, placed a little behind the centre, and raised a trifle above the hinge-line. The hinge-plate and the teeth, including the slender laterals, are white. The interior is somewhat glossy, of the same colour as the exterior, showing a pallial sinus, sharply rounded at the end, and reaching a little more than a third of the length across the valves.
Length 15 mm., height 10, diameter 7.
Ilahitat. — Admiralty Islands, north-east of New Guinea, in 16 to 25 fathoms.
The single specimen under examination may not represent the adult state of this species ; but, judging from its general appearance and the somewhat thickened inner margin of the valve, I am of opinion that it does not attain a large size. It must not be confounded with the young of Mactra achatina, also met with at the same locality. That species has the hinder portion of the valves longest, and lacks the strong grooving on each side of the umbones.
Mactra decora, Deshayes.
Madra decora, Deshayes, Proc. Zool. Soc. Lond., 1854, p. 63. Mactra decora, Reeve, Conch. Icon., vol. viii. fig. 80.
Habitat. — Banda Island.
A single specimen from this locality may possibly be the young form of this species, although I hesitate to afiirm positively that such is the case. The species attains a larger size than the example figm-ed by Reeve, a specimen in the Cumingian collection having a length of 57 mm.
Mactra pusiUa, A. Adams (PL V. figs. 8-8r).
Mactra pusilla, A. Adams, Proc. Zool. Soo. Lond., 18.55, p. 226.
Testa ovato-trigona, fere seq^uilateralis, utrinque subacuminata, tenuis, dilute caeruleo- alba, radiis olivaceo-fuscis numerosis plus minusve distinctis ornata. Umbones mediani, acuti, pur[3urascentes. Ai-ea dorsalis utrinque alba, fusco margiuata. Yalvse nitidse, incrementi lineis tenuibus striatije, utrinque marginem dorsalem versus subfortiter et confertim sulcatiB. Margo dorsi anticus valde declivis, jjaulo convexus, posticus aliquanto convexior, subsequaliter obliquus. Ventris margo regulariter late arcuatus. Pagina interna livido-purpurascens, prope umbones cseruleo-albida, marginem inferiorem versus dilute fuscescens vel cervina. Pallii sinus mediocriter profundus, vix ad medium attingens, ad extremitatem acute rotundatum.
REPORT ON THE LAMELLIBRANCHIATA. 61
This is a thinnish species, nearly equilateral, ovately trigonal, longer than liigli, some- what acuminate at both ends, more especially posteriorly. It is rather glossy, very finely striated by lines of growth, and sculptured on both sides beneath the dorsal line with somewhat strong sulci, which become gradually coarser as the shell increases. The general tone of the valves is light fawn, varied with numerous narrow olive-brown rays, and purple tips to the umbones. The dorsal area has a lanceolate white space in front of the beaks, and a narrower one behind them, which are bordered with a brownish colour. The dorsal margin is very oblique and only slightly curved in front, but rather more arched and about equally sloping behind. The lower outline is regularly and broadly arcuate, forming anteriorly with the upper slope a rather sharply rounded extremity, the opposite end being roundly angulated. The interior of the valves is livid purplish, paler towards the margin, which is fawn coloured, and bluish-white beneath the umbones. The hinge-plate and the teeth are white. The pallial sinus moderately deep, some- what sharply rounded at the end, • and does not reach quite half-way across the valves.
Length 31 mm., height 21, diameter 12^.
Habitat. — Brisbane water, Queensland, di-edged at a depth of 5 fathoms on a sandy and shelly bottom by J. Macgillivray during the voyage of the " Eattlesnake ; " also Port Jackson, New South Wales, in 4 to 18 fathoms (Challenger) ; Moreton Bay (A. Adams).
This is possibly the species referred by Angas ^ to Mactra luzonica of Deshayes, to which it is very closely related. That species is, however, a somewhat thicker shell, a trifle more elongate, having the hinder side rather longer than the anterior, whilst, in the present species, the latter portion is slightly the larger. It is more strongly striated, especially towards the anterior end, where the valves are distinctly concentrically sulcate. It is also almost totally devoid of radiating markings, has no whitish mark beneath the umbones in the interior, and has a smaller and shorter paUial sinus. It is said to have been found at the Island of Luzon, and specimens were collected on the coast of Arakan by W. T. Blanford, Esq., who liberally presented a set, together with a very valuable collection of shells from that country, to the British Museum.
The types in Cuming's collection found at Moreton Bay by Mr. Strange are young shells, and of a paler tint than more adult specimens. The interior also lacks the livid purplish colour so characteristic of the full-grown shell, and the beaks are paler than usual. In aU other respects there is no difference, the form, sculj^ture, hinge and pallial sinus corresponding exactly with the larger specimens from Port Jackson and Brisbane. But little attention must be paid to the colours ascribed to this species by its describer, for I was once informed by Mr. G. F. Angas that ^Ir. A. Adams was colour-blind.
1 J'roc. Zoul. Hoc. Lund., 1867, ]'. UlU.
62 THE VOYAGE OF H.M.S. CHALLENGER.
Mactrajacksonensis, n. sp. (PI. V. figs. 9-9&).
Trigonella pusilla, Angas (non A. Adams), Proc. Zool. Soc. Lond., 1867, p. 916.
Testa parva, paulo inaequilateralis, triangularis, albida, radiis paucis fuscis plus minusve distinctis ornata, tenuis, nitida, striis concentricis tenuibus sculpta. Margo dorsi utrinque valde declivis, vix arcuatus vel subrectus ; margo veutris late arcuatus, parum ascendens. Cardo angustus, dentibus gracilibus munitus. Pallii sinus parvus, minime profundus.
This species is of small size, triangular, considerably acuminate behind, and rather more obtusely rounded in front. It is a little inequilateral, the posterior side being a trifle longer than the anterior. It is thin, glossy, finely concentrically striated, the striae being about as fine at the sides as on the centre of the valves. It is whitish, varied with about six more or less distinct brownish rays. The dorsal margins are almost rectilinear, and rather sloping, especially the posterior, which is a trifle longer than the anterior. The umbones ate small, acute, white, and defined on each side by brownish rays. The interior of the valves is very similar in colour to the exterior, and exhibits a very small delicate hinge and a very shallow pallial sinus, extending only about one fourth of the length across the valve.
Length 14^ mm., height lOg, diameter 6.
Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms.
This species must not be confounded with the young form of Mactra pusilla. It may easily be distinguished by the following difl'erences. It is more acute behind and has the posterior side longer than the anterior, whilst in Mactra pusilla the relative sizes are reversed. The present species too has pale imibones, also lacks the conspicuous sulci on each side upon the dorsal areas, and has a smaller pallial sinus.
Family A n a T i n i d jj.
Subfamily Pandorin^.
Ca'lodon, Carpenter. Coelodon elongatus. Carpenter.
Caelodonelongatus, Carpenter, Proc. Zool. Soc. Lond., 1864, p. 600. Coelodon elongatus, Carpenter, Moll. West. N. Amer., p. 229.
Habitat. — Flinders Passage, North Australia, in 7 fathoms.
The shells originally described by Carpenter were from China and Borneo. The single specimen from the aljove locality difi'ers in one or two points which are not, I consider, of specific importance. The hinder portion of the dorsal line is rather less
REPORT ON THE LA.MELLIBRANCHIATA. 63
incurved, the anterior less oblique, and the left valve has a slight keel extending a short distance oblicpely from the umbones which does not occur in the three specimens examined by Carpenter. These differences probably would not prove constant could we study a large number of examples. In its excessive flatness and the character of the hinge it perfectly corresponds with this species. Ccelodon delicatulus} a Japanese species, has a similar umbonal ridge, but is rather different in form, and has another description of hinge.
Myochama, Stutchbury. Myochama anomioides, Stutchbury.
Myochama anomioides, Stutclibury, Zool. Journ., vol. v. p. 9Y, Tab. Suppl. 42, figs. 1-4. Myochama anomioides, Hancock, Ana. and Mag. Nat. Hist., 1853, vol. xi. p. 287, pi. xi.
(animal). Myochama anomioides, Chenu, Man. Conch., vol. ii. p. 52, fig. 219. Myochama anomioides, Woodward, Man. Moll., pi. xxiii. fig. 13. Myochama anomioides, Reeve, Conch. Icon., fig. 4c only.
Myochama liejypelliana, A. Adams, Proo. Zool. Soc. Lond., 18.52, p. 90, pi. xv. fig. 1. Myochama liepjM'lUaiia, Reeve, Conch. Icon., fig. 2.
Habitat. — Port Jackson on Pectunculus holosericus and Trigonia lamarckii, in 2 to 10 fathoms; also at Station 162, off East Moncceur Island, Bass Strait, in 38 fathoms; sand and shells ; on Pectuncidus beddomei.
I do not find any good characters distinguishing Stutchbury's Myochama anomi- oides and the Myochama keppelliana of A. Adams, and I am also inclined to think that another set of species so-called, namely, Myochama stutchhuryi, A. Adams, Myochama tahida, Reeve, and Myochama tra)7sversa, A. Adams, merely differ from the rest in having the radiating costse finer. I feel, however, no hesitation in pronouncing the three last mentioned forms as one and the same. The remaining species, Myochama strangei of A. Adams, is a very distinct shell from any of those mentioned above, having a peculiarly WTinkled and malleated surface, and moreover of a different colour. I would here remark that Reeve is totally wrong in placing Myochama transversa as a synonym of Myochama strangei, the latter being correctly figured on PI. I. fig. \h.
The type of Myochama transversa still preserved in the Cumingian collection, does not appear in Reeve's Monograph, but was first of all figured in the Proc. Zool. Soc. Lond., 1850, pi. viii. fig. 1, the drawing being enlarged, and subsequent!}^ in the same work for 1852, pi. XV. fig. 3, this figure representing the specimen of its natural size. I do not agree with Reeve in considering the right hand specimen of figure 3 on his plate distinct from the shell on the left, both in my opinion being forms of Myochama transversa, also represented by figs. 4a and 46, Myochama anomioides being delineated by fig. 4c only.
» (A. Adams, MS.\ Carpenter, Proc. Zoo}. Soc. Lond., 1864, p. GCO.
64 THE VOYAGE OF H.M.S. CHALLENGER.
Myodora, Gray.
Myodora pandoriformis, (Stutchbiuy).
Anatiua jiandorifnrmis, Stutclibury, Zool. Journ., vol. v. p. 99, Tab. Suppl. 43, figs. 3, 4.
Myodora 2)undoriform)s, Haiilej', Descrip. Cat. Eec. Biv. Shells, pi. x. fig. 9.
Myodora imndoriformis, Smith, Proc. Zool. Soc. Lend., 1880, p. 581.
Myodora pandoneformis, Eeeve, Conch. Icon., fig. 10 ; Proc. Zool. Soc. Lond., 1844, p. 93.
Myodora brev/'s, H. and A. Adams (non Sowerby), Gen. Eec. Moll., vol. iii. pi. xcviii. figs. 2, 2a.
Habitat. — Port Jackson, Sydney, 2 to 10 fathoms (Challenger, Stutchbury, and Macgillivray) ; ]\Iiddle Harbour (Angas) ; Sydney Heads, 1 5 fathoms (Brenchley) ; Port Philip (Brit. Museum).
This species is easily recognised from the rest of the genus by its transversely elongate form, its comparative smoothness, and the excessive fineness of the microscopic sculpture.
Myodora hrevis (Sowerby).
Pandora hrevis, Sowerby, Appendix to Stutchbury's Sale Catalogue, p. 3, pi. fig. 2.
Anatina hrevis, Stutclibury, Zool. .Journ., vol. v. p. 99, Tab. Suppl. 43, figs. 1, 2.
Myadora hrevis, Eeeve, Proc. Zool. Soc. Lond., 1844, p. 93.
Myadora brevis, Eeeve, Conch. Icon., figs. 7a, h.
Myodora hrevis, Hanley, Cat. Eec. Biv. Shells, pi. x. fig. 13.
Myodora hrevis, Chenu, Man. Conch., vol. ii. p. 52, fig. 217.
Habitat. — Port Jackson, Sydney, 2 to 10 fathoms (Challenger, Stutchbury, and Brenchley) ; Lane Cove, Farm Cove, and Mossman's Bay (Angas) ; Cape Upstart (Mus. Cuming) ; New Zealand, Stewart Island, and Tasmania (Brit. Mus.).
The Myodora hrevis of Woodward's Manual of MoUusca, pi. xxiii. fig. 12, is the Myodora striata of Quoy and Gaimard, and Messrs. H. and A. Adams' identification of this species (Gen. Rec. Moll., vol. iii. pi. xcviii. figs, 2, 2a) is also incorrect, the shell there delineated being Myodora pandoriformis. In my Monograph of this genus ^ I observe that the form of this species is subject to considerable variation. This may be seen by comparing the figure in the Stutchbury Sale Catalogue with that in the Zoological Journal. The series of specimens in the British Museum, too, indicates how variable this species is with regard to outline, the apical angle in some being much more acute than in others. The microscopic sculpture consists of a very minute granulation, the granules being of unequal sizes, and frequently transversely oblong. This granu- lation is coarser than in the other species of the genus, and the almost total absence of the radiating microscopic lines in all of them is remarkable. The Tasmanian specimens are peculiar on account of the greater coarseness of the concentric raised ridges ;
^Proc. Zool. Soc. Land., 1880, p. 580.
EEPORT ON THE LAMELLIBRANCHIATA. 65
but in other respects they agree witli the normal Australian form, except that the umbonal angle is rather less acute.
Myodora crassa (Stutchl)ury).
Anatina crasm, Stutchburv, Zool. Journ., vol. v. \\. 100, Tiili. Su|ipl. xliii. figs. .5, G. Mijodora crassa, Reeve, Proc. Zool. Soc. Lond., 1844, p. 92. Mi/odora crassa, Reeve, Conch. Icon., fig. 1. Myodora crassa, Hanley, Roc. Biv. Shells, pi. x. fig. 6. Myodora crassa, Smith, Proc. Zool. Soc. Lond., 1880, p. 581.
Habitat. — Port Jackson, Sydney, iu 2 to 10 fathoms (Challenger, Stutchbury, Macgillivray, King) ; Middle Hai'bour (Angas).
Only one not quite full-grown right or deep valve was obtained by the Expedition. The species, although small, is remarkable for its solidity, and the less flattened character of the flat or left valve. The microscopic sculpture is fairly coarse, the radiating striae being well marked. In addition to the single valve above mentioned, I have since discovered three very small odd valves which possibly may be the young state of this species. I find in them two ditferences, namely, a larger pallial sinus and no lateral dental grooves in the right valves. Considering, however, the modifications in the hinges of some bivalve shells resulting from age, I think it very possible that these differences in the present instance may arise from a like cause.
Myodora trigona, Reeve.
Myodora trigona. Reeve, Conch. Icon., fig. 2 ; Proc. Zool. Soc. Loud., 1844, \). 92. Myodora tincta. Reeve, Conch. Icon., fig. 5; Proc. Zool. Soc. Lond., 1844, p. 93.
Habitat. — Flinders Passage, North Australia, in 7 fathoms.
A single left valve from this locality diSers from the type from the Philippine Islands merely in having the dorsal margins convergent at a rather less acute angle, so that the form becomes rather more oblong, and a right valve is still less angular and partakes of the form of an adult Myodora oblonga, Reeve. This species may only be the youug form of a variety of that species, being mainly distinguished by rather finer concentric sculpture.
Myodora sp.
Te.sta valva sinistra suba^quilaterali, triangulari, latere antico acute angulato, po-stico oblique truncato, leviter concava, sulco prope margiuem dorsi posticum exarata, concentrice sulcata, interstitiis subrotundatis, pone sulcum radiantem obsoletis, undique microscopice
(zool. chall. EXP. — PART xxxT. — 1885.) Mm 9
66 THE VOYAGE OF H.M.S. CHALLENGER.
interruptim eoncentrice striata, Margo dorsi utriiifjiie valde deseendens, subsequalis, posticus rectiliuearis, anticus levissime couvexus. Margo ventralis late arcuatus, postice Adx adsceudeus. Sinus pallii arcuatus, minime profundus. Pagina interna sulco radianti unico notata.
There is but a single left or flat valve of this species in the collection. It is triangular, nearly eqiiilateral, acute in front, shortly truncated posteriorly, a little concave, concentrically grooved and lidged, the ridges being nearly obsolete behind an impressed ray which runs from the acute umbo to the lower angle of the hinder trunca- tion. The dorsal margins are about equal in length, and converge at an angle of about 60°. The hinder is c[uite rectilinear, except just behind the umlio, where there is the faintest incurvation, the anterior being, on the contrary, slightly excurved. The lower margin is ^videly arcuate, a little up-cur\'ing in front, and scarcely at all at the opposite end. The internal surface is glossy, porcellanous, and marked with a single radiating groove, extending from near the acute recurved beak to the side of the shallow sinus in the pallial line.
Leno-th 7 mm., heio-ht 51.
Habitat. — Flinders Passage, Cape York, North Australia, in 7 fathoms.
The single valve here described approaches il/yoc?oro trigona,liieeYe. It is, however, distinguished by the longer straight posterior dorsal slope, greater concavity of the surface, and the more pronounced radiating groove.
Myodora sp.
Testa elongata, tenuis, paulo infequilateralis. Valva dextra mediocriter convexa postice pone porcam radiantem ab uml)one ad extremitatem posticam decurrentem ali(|uanto excavata, eoncentrice lirata, latere, antico rotunde subangulato, postico oblif^ue truncate. Margo dorsi anterior obliquus, fere rectus, posticus paululum longior, leviterque concavus, declivis. ]\Iargo ventralis latissime arcuatus. Sinus pallii modice profundus, apice subacuto.
Only two right valves of this .species were obtained. They are very elongate, thin, a Uttle inecjuilateral, finelj^ and subdistantly costate, the ridges disappearing at the arcuate angulation which marks off a small depressed portion of the surface at the hinder end. The dorsal margins are subequally oblique, and form at the umbo an angle of about 65°. The posterior is slightly the longer, and a little concave, the anterior being nearly rectilinear.
The lower margin is very gently curved, and forms with the dorsal slope an acutely rounded anterior extremity, the opposite end being broadly truncate in a slightly oblique
EEPORT ON THE LAMELLIBRANCHIATA. 67
direction. The microscopic sculpture is finer at the extremities than on the central portion of the valves, where the radiating striae are clearly developed. The umbo is acute, dii-ected towards the hinder end, and curves over towards the left valve. The pallial sinus is fairly deep and acutely rounded at the end, and is touched by an impressed ray descending from the beaks. The hinder muscular scar is cii-cular, rather high up, aud larger than the anterior, which is a trifle lower down aud subpyriform. The hinge-line and ligament pit are normal.
Length 6|- mm., height 4i.
Habitat. — Stations 187 and 188, Iwth iu the region of Torres Strait, North Australia, at depths of 6 and 28 fathoms.
This species is even more elongate than Myodora. oblonga, in addition to which it is more finely ridged and less acutely beaked at the apex. Myodora pandoriformis is also shorter and more finely microscopically sculptured.
Myodora australica (Reeve).
Thraeia wustralica, Eeeve, Conch. Icon., fig. 1-3.
Tliracia novu-zelandica, Eeeve, Couch. Icon., fig. 19.
Thraeia novo-zelavdien, Hutton, Manual Moll. New Zealand, p. 136.
Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms (Challenger) ; Moreton Bay (Reeve) ; Port Jackson (Angas and Voyage of the " Rattlesnake," in the British Museum).
This, like all the species of the genus, is inequivalve and white, and sculptured with microscopic concentric stride which are interrupted by others radiating irregularly from the umbones, producing a shagreened surface. It is much longer tlian high, somewhat trigonal, acuminate anteriorly, and truncated behind. The right valve is moderately convex and larger than the left, which is much flatter. Both are marked with subplicate lines of growth, and have a slight arcuate angle running from the beaks to the lower posterior extremity, behind which the surface is somewhat concave. The front dorsal margin is elongate, moderately sloping, and very slightly arcuate, the posterior being not quite so oblique, shorter, a little excavated near the umbones, and then straightish. The ventral outline is very gently curved, forming a rounded angle at its junction with tlio posterior side, and joining the anterior dorsal slope in a sharp curve. The umbones are acute, and the area is lanceolate, excavated, and defined by sfight ridges. The dorsal margins of the left (flattened) valve are acute, but at right angles to the rest of the surface, and act as lateral teeth, fitting into corresponding grooves in the other valve. The ligamental scar beneath the beaks is narrow, rather small, moderately deep, and slopes a little towards the posterior end. The anterior scar is long and narrow, the hinder one being shorter and ii-regularly rounded. The sinus in the pallial line is large, deeper than high, rounded at the end, and not extending to the centre of the valves. The internal
68 THE VOYAGE OF H.M.S. CHALLENGER.
surface is dull, roughish, or minutely subgranulated about the middle, smoother, more shining, and radiately substriated towards the ventral margin.
Reeve recognised the general outward resemblance of this form to Myodora, and it is to be regretted that he did not, before describing it, examine the hinge. Had he done so he would at once have perceived that it did not corres^jond with that of TJiracia, but in reality was truly Myodoroid. His conjecture that his TJiracia novo-zelandica might possibly be a variety of Thracia australica is confirmed l;)y the fact that it also proves to belong to Myodora, and the locality " New Zealand " has yet to be confirmed, for, so far as at present known with absolute certainty, the species appears to be limited to New South Wales and Queensland.
Myodora angustata (Angas).
Alicia angustata, Angas, Proc. Zool. Soc. Lond., 1867, p. 908, pi. xliv. fig. L Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms.
At present I see no gi-ounds for separating this species and Alicia^ elegantula, Angas, generically. Both species have the left valve smaller than the right, are white, truncated posteriorly, and sculptured microscopically as in all the species of Myodora. The composition of the hinge in both proves to be identical, and the pallial line is sinuated. The more elongate form and the fact of the left valve l^eing rather moi'e convex than in most other species are not in my judgment characters of any importance from a generic point of view.
Subfamily Thraciin.e.
Thracia, Leach.
Thrxicia meridionalis, n. sp. (PI. YI. figs. 4—46).
Testa paulo iusequilateralis, modice convexa, ovato-oblouga, postice truncata, cariuam obsoletam ab umbonibus ad extremitatem posticam exhiljeus, sordide albida, lineis incrementi rugosis, striisque tenuibus concentrice seulpta,undique minute grano-scobinata; margo dorsi antice valde declivis, aliquanto arcuatus, postice brevior, minus descendens, rectiusculus; margo ventris levis.sime excurvatus, uti'inque parum adscendens. Latus anticum rotundatum, posticum oblique, vix arcuatim tnmcatum. Cardo, cicatrices et lallii sinus fere \\t in TJiracia truncata (Brown).
This species is of an oblong form, rounded in front and squarely truncated posteriorly, slightly inequilateral, the anterior side being a trifle the longer. It is moderately
lis name was previously employed by Mr. .7. Y. Johnson for a remarkable Sea Anemone, Proc. Zool. Soc. Lond., 03.
REPORT ON THE LAMELLIBRANCHIATA. 69
convex, depressed or a little concave l>elund,a faint angulation extending from the umbones to the lower posterior end, thin, dirty whitish, finely concentrically striated, marked with more distinct lines of growth here and there, and everywhere very minutely roughened or subgranulated. The dorsal line is very oblique and moderately arched anteriorly, less descending and rectilinear behind, forming with the side margin, which is almost straight, and slopes inward or towards the middle of the slightly curved lower margin, a rather sharp angle. The hinge is not quite like that of TJirncla fruncata of Brown, the process to which the ligament attaches itself lieing rather slighter, distinct from, and soldered to the hinge-line. The muscular scars and the sinus in the pallial line are similar.
Length 23 mm., height 19, diameter 10.
Length 23 mm., height 18, diameter 9|.
Habitat. — Royal Sound, Kerguelen Island, in 20 to 60 fathoms ; Betsy Cove, in 20 to 25 fathoms ; Marion Island, in 50 to 75 fathoms ; and Prince Edward Island, in 100 to 150 fathoms.
This is the southern representative of the Greenlandic species Thvacia truncata, and indeed differs so slightly from it that it is with considerable hesitation I venture to describe it as distinct, being mainly influenced to do so by the difference of locality. It is not so equilateral, has the ventral margin straighter, the posterior end more abrujitly truncated, the extremity being at the upper angle, whilst in the boreal form the low^er end is usually the most prominent. The hinder dorsal slope in the present species is a little reflexed or bent over in botli valves, forming an indistinct area, which in Thracia truncata is scarely traceable. A more tangible difterenee is in the slighter shelly process which supports the ligament, being, as it were, a separate ])iece joined on to the hinge-line.
Tliracia iratsoni, n. sp. (PI. VI. figs. 5—56).
Testa magna, eomplanata, fere, aequilateralis, utrinque dorsaliterque aliquanto hians, all)ida, concentrice fortiter plicato-rugata, scabra, granulata, transversim oblonga, antice rotundata, postice obbque truncata, margine ventrali rectiusculo rotundatim in latum anterius ambiente. Margo dorsi auticus paulo obliquus, vix arcuatus, posticus valvse dextrse mediocriter concavse horizontalis, in valva sinistra siibplana leviter obliquus, iufi-a umbonem concaviusculus. Umbones parvi, acutissimi, postice inclinati. Area excavata, subacute marginata. Ligamentum externum utroque ajMcis latere pi'olongatum, antice in fossula parva marginam intra situm. Cartilago interna magna, triangularis, in receptaculo calloso crasso inclusa. Cicatrix muscularis posterior fere circularis, anterior elongata, irregularis. Pallii sinus profundus, latus, ad apicem rotundatus.
This magnificent large species is much compressed, very elongate, not quite twice as long as high, almost equilateral, rounded in front, oljliquely truncated at the opposite
70 THE VOYAGE OF H.M.S. CHALLENGER.
extremity, and gapes somewhat at both ends and along the back. It is dirty whitish, concentrically coarsely plicate -wrinkled, the rugse being stronger upon the central portion of the valves, becoming more or less obsolete towards the dorsal margin on both sides. The surface or outer shell-layer is everywhere rough to the touch, minutely granular, and produced in the left or flat valve beyond the white shelly interior, forming a broadish buff border composed of a compact tessellation of thousands of the minutest plates as it were soldered together. The dorsal margin is slightly arcuate on the anterior side and somewhat oblique, posteriorly being almost rectilinear, and horizontal in the right or deep valve, but a trifle oltlique and concave near the beak in the left. In this valve, on both sides of the umbo, it is turned over abruptly, almost at right angles towards the other valve. The lower outline is straightish along the middle, consideraljly up-curving in front, and only a little behind, forming with the oblique latter margin a well-rounded corner. The umbones are small, very acute, not at all inflated, and turn towards the hinder end. On this side the dorsal area is excavated at the beaks, where it is rather sharply margined on each side. The external ligament extends on both sides of the umbones, in front having a narrow short groove partitioned ofl' for its reception. The internal cartilage is large, equilaterally triangular, located in a strong shelly process firmly soldered to the valves immediately beneath the beaks, which is unusual. The muscular scars are high up, the posterior being nearly circular, near the dorsal margin, and somewhat remote from the end of the shell. The anterior is in about the same position, elongate, narrow, bent in the middle. The siphonal inflection of the jjaUial line is deep, broad, rounded at the end, and extends across the valves about five-fourteenths of the entire length of the shell.
Length 58 mm., height 32, diameter 10.
Habitat. — Station 162, oft' East Moncoeur Island, Bass Strait ; in 38 to 40 fathoms ; sand and shells.
This fine large species is remarkable on account of its flattened compressed char- acter, and being almost equilateral. The ligament-pit is very strong, and the outer epidermal shell-layer is peculiar. I have much pleasure in naming it after my friend the Rev. R. Boog Watson, who is carefully preparing a Report upon the Gasteropoda and Scaphopoda of the Expedition.
Thracia myodoroides, n. sp. (PI. VI. figs. 6— 6&).
Testa subcompressa, sequilateralis, aliquanto triangularis, postice late truncata, antice rotunde cuneata, albida, minutissime granulata, incrementi lineis hie illic inconsjiicuis arata. Margo dorsalis anticus valde obliquus, rectiusculus, vix excurvatus, posticus leviter declivis, rectilinearis. Yentris margo parum arcuatus, antice lente adseendens, cum dorsali acuto-rotundatim junctus. Umbones parvi, acuti, latus versus posticum vix
REPORT ON THE LAMELLIBRANCHIATA. 71
iiiclinati. Ligamentum Havum in sulco angusto marginali sitiim. Sinus pallii latus, arcuatus, havid profiiudus.
This species is ouly slightly inequivalve, equilateral, one-third longer than high, moderately convex, ii-regularly triangular, narrowed in front and broadly truncated posteriorly. The valves are white, very finely granulated throughout, exhibit marks of growth at intervals, and have a rounded angle extending from the umbones to the lower posterior extremity, and another subparallel with tlie margin which encloses the dorsal area. The dorsal margin is rectilinear posteriorly and nearly so in front, and almost equally obliijue on both sides, forming at the apex an angle of about 130°. The anterior end is rather wedge-shaped and rounded at the extremity, the posterior side being squarely truncated, forming rounded angles with the dorsal and ventral margins, the latter being but very little curved and rather more ascending in front than behind. The external ligament is yellowish, and located in a narrow marginal groove behind the beaks. The pallial sinus is broad, arcuate, but not deep. The interior is not very glossy and radiately substriated.
Length 13 mm., height 9|, diameter 5.
Habitat. — Station 162, off East Moncceur Island, Bass Strait, in 38 to 40 fathoms.
This species is rather like Myodora australica, Reeve, in respect of form.
T/iJ-acia modesta, Angas.
Thracia modesta, Angas, Proc. Zool. Soc. Lond, 1867, p. 908, pi xliv. fig. 3. Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms.
The left valve of this species is rather shallower than the right. The single valve obtained by the Challenger has the posterior truncated end rather broader than the type figured by Angas, and the lower outline less curved.
Periploma, Schumacher.
Feriploma compressa, d'Orbigny.
Periploma compressa, d'Orbigny, Voy. Am^r. Merid., vol. v. p. 514, pi. Ixxviii. figs. 19, 20.
Testa transversim ovata, antice late rotundata, postice angustior, breviter acuminata, hians, paulo dextrorsum flexa, valde ingequilateralis, subcompressa, sordide, albida aspera, minute grauulata, incrementi liueis striata. Margo dorsi anticus perelongatus, leviter arcuatus et declivis, posticus longe brevior, magis obliquus, primo rectiusculus. Margo ventris late curvatus, postice leviter sinuatus. Umbones parvi, acuti, fissi, circa in i longitudinis coUocati. Ossiculum cardinis ovatum, costa oblic^ua sufFultum. Pagina interna submargaritaeea, linea ai-cuata in valva sinistra ab umbone latum posticum versus radiante notata. Sinus pallii breviter linguiformis ad apicem rotundatus.
72 THE VOYAGE OF H.M.S. CHALLENGER.
This very interesting form is rather compressed, fragile, hroadly ovate, rounded in front, narrower and somewhat pouting posteriorly. It is very inequilateral, minutely granulated, striated by concentric lines of growth, dirty whitish, exhibiting traces of a pale earth-coloured epidermis, which is somewhat reflexed within the valves. The valves are about equal in size, bent a little to the right at the posterior end, and gape somewhat at ])oth extremities, especially behind. The front dorsal margin is slightly convex, very long, and only a little oblique, the posterior being very much .shorter and rather straight at first, then, descending in a slight curve, joins the obliqi;ely up-curving and .slightly sinuated ventral margin at an obtuse point, which is most conspicuous in the left valve. The umbones are small, acute, slit at the apex, and situated at about one-third of the entire length from the hinder end. The cartilage-receiver is more or less ovate, directed obliquely towards the anterior ventral edge, and supported liy a shelly ridge. The transverse free ossicle is moderately thick. The interior of the valves is whitish, a Uttle pearly, exhibits the concentric lines of growth, and one or more radiating lines from the beaks down the posterior side, and apparently more conspicuous in the left valve than the right. The pallial sinus is moderately deep, reaching rather more than one-third across the valves, and is sharply rounded at the end.
Length 37 mm., height 28, diameter 13.
Habitat. — Station 321, off Monte Video, in 13 fathoms ; mud.
The types described by d'Orbigny were collected a little farther south, near San Bias, in North Patagonia.
Lyonsia, Turton.
Lyonsia formosa, Jeffreys (PL YI. figs. 3—36).
Lyonsia funnnsa, Jeffreys, Proc. Zool. Soc. LonJ., 1881, p. 93l), [il. Ixx. fig. 1.
Habitat. — Station 8, off Gomera, Canaries, in 620 fathoms ; sandy mud and shells. (For further distribution, see Jeffreys, loc. cit.)
The Challenger specimen is oblong and somewhat quadrate, having two distinct ridges radiating from the umbones, one to the ventral margin at a point a little l)ehind the middle, and the other to the posterior lower extremity, the former being rounded and subnodose and the latter even, rather acute, and bearing a series of granules rather larger than those on the rest of the surface. Both ends are gently curved, and the lower outline is a little sinuated on each side of the subcentral carina. Behind the posterior keel the valves exhibit about seven slender feeble radiating ridges, each with a row of granules along the top, which are similar to those upon the carina. Within the valves there are seven corresponding faint furrows which have a subpunctate appearance.
REPORT ON THE LAMELLIBRANUUIATA. 73
Lyonsiella, M. Sars. Lyonsiella jeffreysii, n. s^]i. (I'l. XXV. figs. 1-1/^).
Testa tenuis, globosa, inajquilatenilis, aiitice rcctc truucata, postice et iiifonic arcuata, sordide albida, intus margaritacea, undique minute granulata, lineis gracillimis numerosis radiantibus instructa, striisque incrementi hie illic sublamellatis oruata. Margo dorsi anticus brevis, rectus, horizontalis, posticus longior, declivis, vix excurvatus. Lunula concava, tota in valva dextra. Umbones incurvati, antrorsum versi. Cardo edentulus. Ligamentum internum, callo parvo sustentutuni.
This species is thin, convex, inequihxteral, a little higher than long, perpendicularly truncated in front, rounded behind and along the ventral margin. The front dorsal line is horizoual and straight, and at the termination forms a sharp angle with the anterior side. The posterior dorsal edge is rather oblique and nearly rectilinear. The valves are dirty whitish, dull, somewhat pearly within, everywhere finely granuhu', and also sculp- tured with many (about fifty) fine hair-like raised lines and a few concentric lines of growth at intervals, distinct and almost lamellar. The umbones are somewhat incurved, and directed towards the front. The lunule is concave, smooth, extends to the end of the dorsal margin, and is entirely in the right valve. It projects a little beyond the level of the rest of the margin of the valve, and fits into a slight emargination in the corre- sponding part of the left valve. The hinge-line is altogether destitute of teeth, and the ligament is internal and supported by a small shelly ossicle underneath. The front adductor scar is high up, just under the front dorsal margin, the posterior one being lower down, at the end of the dorsal slope.
Length 19 mm., height 20, diameter 14.
Habitat. — Station 106, Mid Atlantic, in 1850 fathoms; Globigerina ooze.
The preserved animal of this fine species appears to agree very closely with the description of Lyonsiella by Sars in Eemarkable Forms of Animal Life, p. 25.
It has a single branchial plume on each side, no labial palps, and a byssiferous foot. The anal and branchial siphonal orifices are distinct, the latter being surrounded by papillae.
Lyonsiella 2'xipyrcicea, n. sp. (PI. XXV. figs. 2-21)).
Testa magna, tenuissima, alba, rotunde cordata, globosa, liris filiformibus numerosis radiantibus ornata, incrementi lineis tenuibus sculpta, epidermide tenuis.sima sordide albida induta. Umbones prominentes, antemediani, valde incurvati, antrorsum versi. Linea cardinalis edentula, tenuis. Ligamentum internum, parvum, paulo pone umbones situm, callo crassiusculo sufFultum. Pagina interna nitida, submargaritacea, radiatim striata, striis cum liris externis congruentibus.
(ZOOL. CHALL. F.XP. — PART XXXV. 188.5.) Mill 10
74 THE VOYAGE OF H.M.S. CHALLENGER.
This fiue species is excessively thin, globose, roundly heart-shaped, inequilateral, transparent wliite, but rendered rather opaque by a thin dirty-white epidermis. The sculpture consists of numerous (about forty) very slender hair-like lines, which radiate from the beaks to the outer margin. They are fairly equidistant, and cover the whole surface with the exception of a small space in front of the umbones. The valves are also very finely striated by the lines of gi'owth, a few at intervals, which apparently mark periods of arrested enlargement, being quite conspicuous. The umbones are large, prominent, well incurved, situated considerably in front of the centre, and inclined over towards the anterior side. The hinge-margin is very thin, and absolutely toothless. The principal ligament is short, entirely internal, attached under the dorsal margin a little behind the umbones, and supported or strengthened underneath by a rather strong callosity, which is rounded beneath, and deeply notched at the hinder end. In addition the valves are connected by a thin ligament along the hinder dorsal edge. The interior of the valves is glossy, somewhat pearly, and feebly radiately grooved, the fine striae corresponding with the external lirse.
Length 23 mm., height 24, diameter 16.
Habitat. — Station 157, about 1100 miles south-west of Australia, in 1950 fathoms; Diatom ooze.
Of this fine species only a single much crushed specimen was obtained. It differs from Lyonsiella Jeffrey sii, with which it agrees in the character of the hinge and ligament, in form and in wanting the fine granulation on the surface.
Lyonsiella grandis, n. sp. (PI. XXV. figs. 3-36).
Testa tenuis, inflata, valde injequilateralis, alba, epidermide tenuissima pallide straminea plus minusve induta, liris filiformibus radiantibus crebris ornata, incremeutique lineis subcancellata. Margo dorsi anticus brevissimus, posticus paulo declivis, I'ectus. Margo ventral is semicircularis, postice oblique in latus arcuatim ambiens. Latus anticum obliquum, in medio rectiusculum, utrinque rotundatum. Umbones magui, pileiformes, jirominentes, conspicue latus versus anticum iuvoluti. Cardo edentulus. Ligament! sulcus interni angustissimus, brevis. Cicatrix antei'ior formse elongatse irregularis infra umbones sita, posterior major prope medium latevis. Impressiones du« minores infra lineam cardinis collocatse.
This species is very thin, considerably inflated, very inequilateral, higher than long, white beneath a somewhat thin pale yellowish epidermis. The valves are very finely and closely radiately Urate, and exhibit rather distinct, elevated lines of growth which almost produce a cancellated appearance.
The umbones are inflated, prominent, cap-shaped, much curved over towards the fi'ont.
REPORT ON THE LAMELLIBRANCHIATA. 75
having the apices rolled up remote from one anotlier and the hinge-line, and situated quiti- near the anterior end. The posterior dorsal margin is rather straight, onl}'' a trifle oblique, and joins the broadly arcuate lateral outline in a well-rounded curve. The anterior portion of the upper mai-gin is very short, forming merely a rounded angle with the obliquely truncate, almost rectilinear, anterior side. The ventral outline is semicircu- larly curved, and more gently ascending posteriorly than in front. The interior is white, glossy, and apparently more or less iridescent. The anterior muscular impression is elongate, of an irregular form and high up, just beneath the umbones. Behind there are three impressions, one (the largest of all) is situated about the middle of the posterior side, the two others being under the dorsal margin. The hinge-line is simple and toothless, having a thin external ligament attached to the edge along nearly the whole extent. The internal Ligament is very slender, located in a very narrow groove, near, but within tlic edge, and probably supported by a free ossicle.
Length 14 mm., height 16, diameter 12.
Habitat. — Station 133, Mid South Atlantic, in 1900 fathoms; Globigerina ooze.
Only a single dead specimen of this fine species was obtained. It differs from Lyonsiella papyracea, not only in form and smaller size, but also in having much more numerous lirse.
Silenia, n. gen.
Testa tenuis, ovato-oblonga, iutus margaritacea, concentrice striata, sparsini granulata; cardo edentulus ; ligamentum externum, marginale. Animal ovato-oblongum, convexiusculum ; pallium inferne apertum, postice siphones infra clausum. Apertura siphonalis papillis elongatis couicis scabris circumdata ; sipho branchialis magnus, externe hand prominens, intus in tulja magna productus, anali contra minimo, externe paulo exstanti, intus baud prolongate ; pes parvus, gracilis, sulco byssali baud aratus. Papillae oi'ales inajquales ; anticse permagnse, posticse parvse. Branchite insignes, utrinque in s(M"ie interrupta, posticeque serie altera transversa etiam in medio interrupta digestae.
This remarkable form differs from Lyonsiella in possessing well-developed labial palpi, in the character and disposition of the branchiae, and one or two points with regard to the siphonal opening and the foot, &c. The shell may be distinguished from that of Lyonsiella by the difference in the hinge-characters, the latter genus having an internal ligament supported by a free ossicle, whilst in Silenia it is external and without a shelly support.
Sileriia sarsii, n. sp. (PL XXV. figs. 4-46).
Habitat. — Station 157, about 1100 miles south-west of Australia, in 1950 fathoms; Diatom ooze; also Station 325, east of the mouth of the Rio de la Plata, in 2650 fathoms: blue mud.
76 THB VOYAGE OF H.M.S. CHALLENGER.
The soft parts of two specimens and a few fragments of the shells adhering to them were alone obtained. From these it is evident that the species is rather large, probably about 20 mm. in length. The shell is excessively thin, prettily iridescent within and faintly so on the outside, which is more or less covered with a thin filmy pah; yellow epidermis, which towards the outer margin of the valves is produced into oldiquc thread-like lines, and somewhat reflexed within. The sculpture consists of distinct concentric lines of growth, a few subdistant hair-like radiating lines chiefly observable near the outer mai'gin, and very minute rather irregularly scattered granules which appear to be most numerous and more i-egularly arranged on the anterior side. The umbones are white, smooth, incurved, and incline towards the front. The hinge-line is rounded and quite toothless in both valves. The ligament is external, strongish, and attached to the edge of the valves.
I cannot discover any sufficient reasons for separating the Australian and American specimens of this very interesting species. They agree exactly as regards the hinge, the fragility of the valves, the epidermis, and the character of the sculpture, the Atlantic example, however, exhibiting rather more distinct granulation. The animals also are precisely alike, even the number of papillas surrounding the siphonal openings being precisely the same, namely fifteen. This is another instance of the remarkable distribu- tion of some deep-sea forms.
Suljfamily Anatinin^.
Anatina, Lamarck. Anatina siphonafa, Reeve.
Anatina siphonafa, Keeve, Conch. Icon., vol. xiv. pi. i. tig. 2. Habitat. — Station 208, Philippine Islands, at a depth of 18 fathoms ; l>lue mud.
The Challenger specimen is a little larger than the ty[:)e, and almost exactly of the same form. I think it probable that Anatina Jiexuosa, Reeve, Anatina cumingii, Valenciennes, Anatina amphora, Reeve, and one or two other so-called species, together with that under consideration, are merely variations of one and the same form.
Anatina elliptica (King and Broderip), juv.
Anatina elliptica, King and Broderip, Zool. Journ., vol. v. p. 3.3.5. Anatina dliptica. Reeve, Conch. Icon., vol. xiv. fig. 14. Anatina elliptica, Griffith's Anim. Kingd., vol. xii. pi. xxii. fig. 3. Anatina prismatica, Sowerby, Proc. Zool. Soc. Lond., 1834, p. 87.
Testa juvenis fragilissima, oblonga, transversa, antice rotuudata, postice lata, arcuatim truncata, inasquilateralis, alba, concentrice rugose striata, sulco obliquo baud profundo ab
KEPORT ON THE LAMELLJBRANC}II AIA. 77
umlionibus ii.s(jue ml cxtrcmitatem iuferioicni postieam arata, radio parum elevato iimboues infra subperpeudiculari interdum vix conspicuo instructa. JVIargo dorsi anticus obliquus, leviter arcuatus, posticus longior, liorizoutalis, prope umbones concavus. Ventris marge rectiusculus. Latus antieum l)revis, subacute rotundatum, vix hians, posticum latum, apertissimum. Umbones parvi, acuti, ante medium siti. Cartilage interna inter callos duos minutos posita ; pagina interna uitida, plus minusve prismatica, superne infra umbones porca obli(|ua gracili, tubcrculo juncta, margine minute dentate instructa.
This shell is oblong, half as long again as high, very thin and fragile, semitransparent white, concentrically rather coarsely wrinkled and striated, exhibiting on each valve a shallow groove radiating from the umbones to the lower posterior extremity, and towards the front having (but not always) a faintly elevated ray, which falls almost perpendicularly beneath the beaks to the ventral margin. It is rather inequilateral, much gaping, broad and arcuately truncated posteriorly, uarrow^ed and somew^hat sharply curved in front, and straightish along the lower outline. The anterior dorsal slope is obliquely descending and faintly convex, the posterior being a little concave near the beaks, and then horizontal or even a trifle ascendant. The umbones are small, acute, and h cated rather in front of the centre. The hinge-cartilage is placed between two minute shelly processes from which diverge in an oblique dii'ection towards the hinder extremity of each valve a slender elevated ridge, the edge of which, under the microscope, is seen to be minutely serrated or dentate. The muscular scars and mantle-impression are indistinct.
Length 12 mm., height 8, diameter 5.
Habitat. — Betsy Cove, Kerguelen Island, in 15 to 25 fathoms, January 9, 1874 ; and Eoyal Sound, Kerguelen Island, in 28 fathoms.
A specimen of this species, more than two inches in length, was collected at Cumber- hind Bay, Kerguelen Island, during Captain Eoss' voyage, and is now in the British jMuseum. In the same collection are two or three others from New South Shetland, (me presented by Captain P. P. King, E.N., being the type described by himself in conjunction with Mr. Broderip. In the adult shell, which is rather solid and beautifully pearly under the external calcareous surface, the internal septum loses its denticulate character.
The muscular scars are high up near the dorsal margin, both being ef an elongate form. The sinus in the pallial line is very wide, and varies somewhat in depth in different specimens. The adult shells show considerable variation in the relative length of the two sides. Some specimens are almost equilateral, whilst others have the anterior portion longer than the posterior, the reverse l)eing the case with the young individuals. The figure given by Eeeve gives a i-ather unusual up-curving of the hinder dorsal margin,
78 THE VOYAGE OF H.M.S. CHALLENGEK.
and represents a shell somewhat higher than usual. The epidermis, judging from thf^ slight remains on this specimen, is rather thick and fibrous.
Family S A x i c a v i d .e.
Saxicava, Fleuriau de Bellevue.
Saxicava arctica, Linn^.
Habitat. — Station 75, oiF Faj'al, Azores, in 500 fathoms. Station 313, Strait of Magellan, in 55 fathoms; off Nightingale Island, Mid South Atlantic, in 100 to 150 fathoms. Stations 141 and 142, off the Cape of Good Hope, in 100 to 150 fathoms; Marion Island, in 100 fathoms; Prince Edward Island, in 150 fathoms. Station 150, south of Kerguelen, in 150 fathoms. Station 311, West Patagonia, in 245 fathoms ; and lastly, at Port Jackson, Sydney, in 2 to 10 fathoms.
This polymorphous species, judging from the shells alone, is apparently distributed all over the globe. Of the animals inhabiting them we know nothing except those of northern varieties. The shells vary immensely in form, thickness, and ornamentation. Those found off the South African coast are especially remarkable for the great development of the spines on the posterior side, and have been raised to specific rank by Mr. Sowerby (Conch. Icon., vol. xx. fig. 12) under the name of Saxicava spinifera. Many localities have already been cited for this species, and among them may be mentioned Greenland, Norway, Great Britain, Sitka, Japan, California, Peru, Patagonia. Canaries, Madeira, Mogador, Mediterranean, Madagascar, Cape of Good Hope, Australia. New Zealand, &c.; and it is also found fossil in several Upper Tertiary formations.
Family S o l e n i d .e. Solen, Linne. Solen sloanii, Gray.
Solen sloanii, Gray, MS. Brit. Mus.
Solen sloanii, Hanley, Cat. Biv. Shells, 1843, jjp. 12 and 336, pL xi. fig. 18.
Sole^i sloanii, Angas, Proc. Zool. Soc. Lond., 1867, p. 912.
Solen sloanii, Sowerby, Conch. Icon., vol xix. pi. iii. fig. 10.
Solen versicolor, Philippi, Abbild., vol. iii. p. 43, pi. ii. fig. 3.
Solen pMHjtpianus, Dunker, MS. in Mus. Cuming.
Solen philippiamis, Sowerby, loc. at, fig. 13.
Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms.
REPORT ON THE LAMELLIBRANCHIATA. 79
I have been unable to discover any description by Dunker of Solen philippianus, no mention of it being made in the Proc. Zooh Soc. Lond. for 1861 as stated by Sowerbv.
SolecuTtu-'i, Blainville.
Solecurtus (^20?') coarctatus (Gmelin).
Solen roarctatus, Gmelin, Syst. Nat., p. 3227.
Solen angusfior, &c., Cliemiutz, Concli.-Cab., vol. -vi. p. 62, pi. vi. fig. 4.5.
Solecurtus ahbreviatus, Gould, Proc. Bost. Soc. Nat. Hist., 1861, vol. viii. p. 26; Otia, p. 164.
Solecurtus abbreviatus, Sowerby, Concli. Icon., voL xix. figs. 6a-b.
Macha abbreviatus, Conrad, Amer. Journ. Conch., vol. iii., Appendix, p. 23.
Macha schcejmiakeri, Dunker, Zeitscli. f. Mai., 1852, p. 56.
Azor (Macha) scheepmaJieri, Dimker, Novitat. Conch., p. 121, pi. xxxix. figs. 10, 11.
Solecurtus scheepmalteri, Sowerby, loc. cit., pi. iii. fig. 14.
Azor oblongiis, Dunker, Proc. Zool. Soc. Lond., 18G1, p. 425.
Solecurtus oblongus (Dohrn), Sowerby, loc. cit., fig. 2.
Azor solidus, Dunker, Proc. Zool. Soc. Lond., 1861, p. 425.
Solecuiius solidus (non Gray), Sowerby, loc. cit., fig. 3.
Habitat. — Station 188, south of New C4uinea, in 28 fathoms; mud.
This species may be known l^y the de^aressed ray, which descends obHc[uely across the middle of the valves. In this respect it differs from the European Solecurtus anti- quatus, and it is also more inequilateral. Chemnitz, in his description, remarks upon this depression, and it is strongly depicted in his figure. On this account, and also for the reason that his specimen came from the Nicobar Islands, I am inclined to agree with Jeffreys in considering this distinct from the British Solecurtus antiquatus. All the forms above mentioned agree in having the radiating groove, a similar epidermis, &c., and differ only slightly in form. Solecurtus ahbreviatus was described from Chinese examples, Solecurtus solulus, Solecurtus ■■icheepmakeri, and Solecurtus oblongus being quoted as Philippine forms. Sowerby (Conch. Icon., fig. 3) represents the type shell described by Dunker as Azor solidus, but refers the species to the Solen solidus of Gray. If Mr. Sowerby had read the description in the Spicilegia Zoologica, p. 7, pi. iii. fig. 12, he could not have made such an unpardonable mistake. Gray's shell has been figured by Reeve in his monograph of the genus Psammohia, pi. iii. fig. 18, as a manuscript species, he not being aware of its description having been published many years previously : and it is a curious coincidence that this same species w-as subsequently described and figured by Philippi as a Psammohia (Abbild., vol. i. pt. 4, p. 1, pi. i. fig. 1) under the siime specific name (solida) employed originally by Gray.
80 THE VOYAGE OF H.M.S. CHALLENGER.
Family P A p h 1 1 d ^. ErvUia, Turton.
Evvllia castanea (Montagu).
Donax castanea, Montagu, Test. Brit., part ii. p. 573 ; Supiil., pi. xvii. fig. 2. ErvUia castanea, Forbes and Hanley, Brit. Moll., vol. i. p. 341, pi. xxxi. figs. .5, 6. Krrilia castanea, H. & A. Adams, Gi'neia Moll., vol. iii. pi. cvi. figs. 7, 7a.
Amphidesma castanen, Je(fre3's, Brit. Conch., vol. ii. p. 413; vol. v. pi. xliiL fig. 1 ; Proc. Zool. Soc. Lond., 1881, p. 922.
Hahitaf. — Stations 75 and 78, off the Azore.s, in 450 and 1000 fathoms ; also off Tenerife, in 70 fathoms.
For the distribution of this species, vide Jeffrey's paper in the Proc. Zool. Soc. Lond.
The West Indian Enjcina nttens, Montagu, is very like this species, and is mainly distinguished by its rather coarser concentric sculpture and different colouring. The composition of the hinge is identical.
Ervilia hlsculpta, Gould.
Ei-vilia hisadjila, Gould, Proc. Best. Soc. Nat. Hist, 18G1, vol. viii. p. 28 ; Otia, p. 1G6. Erivlia australis, Angas, Proc. Zool. Soc. Lond., 1877, p. 17.5, pi. xxvi. fig. 21. Ervilia incolor, DosLayes, MRS. iu Brit. JIus.
Habitat. — Port Jackson, Sydney, in 2 to 10 fathoms (Challenger and Angas) ; off the Pteefs at Honolulu, Sand^^^ch Islands (Challenger) ; Kagosima, Japan (Gould) ; Island of Samar, Philippines (Mus. Brit.).
Australian specimens of this species appear to be rather more finely concentrically striated than those from Japan, judging from a single examjsle in Cuming's collection from that locality. Although Gould refers only to radiating sculpture on one side, I find it occurring on both, in all specimens.
Ervilia sitbcancellata, n. sp. (PL VI. figs. 2-2?^).
Testa subtrigona, acuminate ovata, snbtennis, parva, alba vel roseo tincta, 2"/auk) insequilateralis, concentrice tenuiter lirata, liris ad latera atteuuatis, striis tenuibus radiantibus postice decussatis. Margo dorsi posticus elongatus, fere rectilinearis leviter declivis, anticus brevior, vix excurvatus et obliquus. Umbones parvi, parum prominentes, sul)acuti, apicibus postice versis, paulo ante medium coUocati. Cardo ut in Ervilia castanea.
This species is considerably longer than high, triangularly oval, not very thin, white or stained with rose, chiefly on the posterior portion. It is a little inequilateral,
REPORT ON THE LAMELLIBRANCHIATA. 81
moderately convex, and sculptured with fine concentric lirse, which become more slender at the sides, and are crossed chiefly on the hinder part by fine radiating striae. The dorsal mai-gin is angled at the beaks, and descends about equally on both sides, the posterior portion, however, being rather longer than the anterior. The ventral outline is broadly arcuate, about equally ascendant on each side, and forms, together with the dorsal slope, acutely rounded extremities at both ends. The beaks are not much elevated, small, moderately acute, and curved over at the tip towards the hinder end. The hinge consists of a central large triangular cartilage-pit in both valves, which in the right is bordered in front with an erect oblique prominent tooth fitting into a corresponding deep groove in front of the cartilage-pit in the left valve. The anterior of the valves has a short ridge or thickening, which, arising beneath the umbones, descends to the inner side of the anterior muscular impression.
Length 5 mm., height 3|, diameter 2.
Habitat. — Station 33, off Bermuda, in 435 fathoms; coral mud. Station 113a, off Fernando Noronha, in 25 fathoms ; and Station 120, ofl" Pernambuco, in G75 fathoms.
This species is very like Ervilia nitens, but apparently does not attain such large dimensions. It is more finely concentrically striated and prettily cancellated down the posterior side. In some instances, however, the radiating striaB extend more or less over the entire surface. There are specimens in the British Museum from St. Thomas and St. Vincent in the West Indies.
Ervilia sandwichensis, n. sp. (PL XXV. figs. 5-56).
Testa infe(]^uilateralis, compressiuscula, ovata, all^a, liris concentricis tenuibus aliisque radiantibus concinne granoso-cancellata. Margo dorsi posticus leviter declivis, rectiusculus vel levissime arcuatus, anticus longior, prope umbones j)eculiares tubercu- liformes et rufescentes paulo concavus. Latera sequaliter subacute rotundata ; margo ventris late arcuatus.
This species is pure white, with the exception of the minute tuberculiform embryonic tips of the umbones, which are of a reddish tint. It is transversely ovate, equally and rather sharply rounded at the sides, and broadly curved beneath. It is somewhat compressed and inequilateral, and sculptured with numerous slender concentric lirae, and others which radiate from the beaks, forming a very pretty cancellated surface, as the points of intersection are more or less nodulose.
The structure of .the hinge is normal as in Ervilia castanea. The interior is very glossy, and, owing to the transparency of the shell's texture, the external ornamentation is visible.
Length 3 mm., hieght 2, diameter \\.
Habitat — Off the Reefs at Honolulu, Sandwich Islands, in 40 fathoms.
(ZOOL. CHALL. EXP. — PART XXXV. 1885.) Mill 11
82 THE VOYAGE OF H.M.S. CHALLENGER.
Only a single minute valve of this species is at present known, which probably does not nearly approach the full size it attains in a more adult condition. Considering the distinct character of the sculpture, and that it is very different from all the known species, I have thought it advisable to describe this species although represented by such slight material.
Davila, Gray.
Davila (?*) umbonata, n. sp. (PI. VI. figs. 1-1^).
Testa transversim ovalis, mediocriter insequilateralis, albida, polita, incrementi lineis concentricis irregularibus sculpta. Umbones alti, product!, ad apicem erosi. Latus anticum breve, acute rotundatum, posticum longius, latius curvatum. Margo dorsahs anterior levissime arcuatus, valcle obliquus, posterior minus descendens, subrectilinearis, ventralis late arcuatus. Dentes cardinales tres in utraque valva, cjuorum duo ante liga- meutum siti sunt. In valva dextra anterior gracilis, prope marginem locatus, in sinistra medianus minimus. Impressioues musculares irregulares, antica minore. Linea pallii postice vix siuuata. Cartilage interna magna, fusca. Ligamentum aliud linearis infra umbones situm.
The shell is thinnish, white, glossy, and striated by fine lines of growth, at intervals some of the strise being deeper than the rest, as if marking off periods of growth. In front a large lunule is marked off by a faint line not seen by the naked eye. The form is nearly transversely oval, except that the dorsal outline is interrupted by the beaks, which are situated a little excentrically and rather nearer the anterior side. They are eroded at the tips, a trifle prominent alcove the hinge-line, and scarcely turned towards the front. The hinge is composed of three unequal and divergent teeth in each valve, a largish internal cartilage having two of the teeth in front and the third posterior to it, and in addition a linear ligament along the dorsal edge immediately under and on both sides of the tips of the umbones. In the right valve the foremost tooth is slender, close to and parallel with the outer edge of the valve. The second or median tooth is also slender, a trifle larger than the anterior, from which it diverges somewhat, yet having a forward direction. The hindmost, likewise narrow, inclines backwards, and is separated from the outer edge by a deepish groove. In the left valve the anterior tooth is decidedly the largest, separated from the margin with which it is subparallel by a deepish furrow. The posterior is somewhat smaller, prominent, and close to the outer edges, and the median one is very small, just under the umbo, and scarcely rises to the level of the dorsal margin. The interior of the valves is glossy and white. The muscular impressions are subequal in size and rather irregular in outline. The pallial line is rather remote from the ventral margin, and exhibits the slightest indication of a j)osterior sinus or emargination.
REPORT ON THE LAMELLIBRANCHIATA. 83
Length G^ mm., height nearly 5, diameter 3|,
Habitat. — Off Royal Sound, Kerguelen Island, depth 25 fatlioms; also Prince Edward Island, 150 fathoms, and j\Iarion Island, 100 fathoms.
Variety. — This form is more compressed than the type, thinner, higher in proportion to the length, with smaller, less inflated, non-eroded beaks, and the line cu'cumscribing the lunule is less distinct.
Length 7 mm., height 5f, diameter 3.
Habitat. — Balfour Bay, Royal Sound, Kerguelen, in 20 to 60 fathoms.
The specimens from Prince Edward and Marion Islands, which, I believe, belong to this species, ax-e all young, and in this state do not exhibit any trace of a lunule.
This species does not quite correspond in the hinge with the t}ijical form of Davila, Davila 2^lci>ia of Hauley having in the left valve a small, anterior, lateral tooth, which is absent in Davila iimbonata. The very insignificant emargination of tlie pallial line i."^ equally apparent in both.
Family S c R 0 B I G-u L A R 1 1 D ^.
Subfamily Semelik.e.
Semele, Schumacher. Semele amabilis, A. Adams.
Semele amahilis, A. AJams, Proc. Zool. Soc. Lond., 18.53, p. 97. Amphidesma amabilis. Reeve, Conch. Icon., vol. viii. pi. v. fig. 32.
Habitat. — Station 189, Arafura Sea, in 25 to 29 fathoms, green mud (Challenger); Port Curtis (A. Adams).
This is a very elegant shell, and remarkable on account of the thin elevated and uji- turned concentric lamellae which adorn the surface. It is somewhat longer than high, moderately compressed, almost equilateral, white and stained with brown down the posterior side of the left valve. The front dorsal slope is somewhat concave near the umbones, then oblique and straightish, the posterior being a little arched and scarcely so sloping. The ventral margin is regularly curved, and forms in front, together with the dorsal edge, a broadly rounded end. The hinder extremity is more irregular, termin- ating in an obtuse angle, and exhibiting more or less of an oblique truncation below the angle. The two valves are not similar at the posterior part. In the left there is a single broadish depression radiating from the beak, subparallel with and only a short distance from the hinder dorsal marijin, causing a flexure in the concentric lamellae. In the right valve there are two such depressions and a corresponding double sinuosity of the lamellae. The lunular depression is pretty deeply lanceolate, and the hinder dorsal area is also narrow, sunken, and defined by carinate edges. The sculpture consi.sts of the remark-
84 THE VOYAGE OF H.M.S. CHALLENGER.
able concentric lamellse which are peculiarly curled upwards, strongly Urate, and minutely cancellated on the lower side. In addition to these lamellae there are finer concentric lirse between, usually one in each interstice. Beside these the whole surface is densely and minutely sculptured with microscopic radiating thread-like lines, which are not so apparent as those upon the lamellae. The hinge is composed of two minute cardinal teeth in each valve and two moderately developed laterals, whereof the posterior is rather more remote from the apex of the umbones than the anterior. The internal cartilage is long and narrow, and the external ligament, which is somewhat shorter, is slight. The interior of the valves is white, and exhibits a number of faint radiating depressions, one of them, which crosses the anterior muscular scar, and is, as it were, a continuatioli of the pallial line, being particularly noticeable. The pallial sinus is directed upwards, obtuse at the extremity, and reaches about half-way across the valves. The specimen obtained by the Challenger is rather larger than the type described by A. Adams, being 66 mm. long, 52 high, and 25 in diameter.
Semele ohliqua (Wood), juv.
Tellina ohliqua, Wood, Gen. Conch., p. 152, pi. xli. figs. 4, 5. Amphklesma ohliqua, Eeeve, Conch. Icon., vol. viii. pi. i. figs. 5a-h. Amphidesma variegata, Lamarck, Anim. s. Vert., ed. 2, vol. vi. p. 126. Davila variegata, Clieuu, Man. Conch., vol. ii. p. 80, fig. 346.
Habitat. — Station 122, off Pernambuco, Brazil, in 350 fathoms; red mud.
Only a single young specimen half an inch in length was obtained. It is whitish, Ijlotched on the dorsal margin and towards the beaks with pinkish-red, and speckled in the same region with opaque white. The great depth at which this shell lived probably will account for the paleness of its colouring, which is much more vivid in all the other specimens that I have seen.
Semele infans, n. sp. (PI. V. figs. l-\h).
Testa parva, oblique rotundato-subtrigonalis, ina^quilateralis, alba, nitida, iucrementi lineis sculpta, lunula distincta, lanceolata antice instructa. Umbones acuti, post medium siti, anticam partem versus inclinati. Margo dorsalis posticus valde descendens, arcuatus, anterior prope umbones concaviusculus, deinde excurvatus, ventralis late rotundatus, postice subsinuatus. Dentes cardinales duo iu valva dextra, uuus in valva altera. Fossae laterales valvae dextrae magnae, latae, usque ad umbonem utrinque extensEe.
The shell is minute, longer than high, thin, glossy, and sculptured with fine yet distinct lines of growth. It is of a roundish subtriangular form and inequilateral, the anterior end being the longer and regularly sharply curved, whilst tlie opposite side
REPORT ON THE LAMELLIBRANCHIATA. 85
terminates in a much more acute extremity, and indeed might be described as subrostrate. The posterior slope descends rather suddenly, and is only a little arcuate, the front margin being less oblique and more excurved, except in the lunula r region, where it is slightly concave. The ventral outline is regularly and widely curved except near the liimlcr end, where it is feebly sinuated, which gives the subrostrate appearance to that portion of the shell. The lunule is lanceolate, narrow, and bounded by a raised ridge on each side. There is but a single cardinal tooth in the left valve, about equal in size to either of the two in the right valve, which are divergent and united at their upper extremities. The anterior does not stand separated, but is united to the ridge which forms the inner side of the lateral groove. Those on l)oth sides commence at the beaks, extend a considerable way down the dorsal margin, and are wide and deep, receiving the i^rominent corresponding margins of the left valve. The internal ligament is elongate, narrow, and posterior to the cardinal teeth. The muscular scars and pallial impression are not clearly definable owing to the condition of the interior of the valves. The posterior of the former appears to be pyriform, rather large, and broader than the front one. The sinus in the mantle line is probably large.
Length 3f mm., height 3, diameter 1^.
Habitat. — Flinders Passage, north of Cape York, North Australia, at a depth of 7 fathoms.
The line on each side parallel with the dorsal margin shown in fig. 1 is merely the inner edge of the hinge-plate, which is visible externally owing to the transparency of the shell
Semele [Ahra) braziliensis, n. sp. (PI. V. figs. 2-26).
Testa sequilateralis, compressa, tenuis, alba, pellucida, concentrice exiliter striata, nitida, transversim elongata, postice acuminata, antice latior, rotundata. Margo dorsalis utrinque fere rectilinearis, pone obliquior quam ante. Area elongata, planata. Umbones centrales, parvi, acuti. Lunula angusta, baud profunda. Dentes cardinales valvse dextrse subsequales, divergentes, superne conjunct!. Fossae laterales angustse, postica ad umbonem baud pertingens. Ligamentum internum valde obliquuni, angustum. Sinus pallii profundus, ad extremitatem subacutus.
The shell is very thin and fragile, transparent, equivalve, flattened, glossy, striated with very fine lines of growth, and sculptured with microscopical longitudinal stria? not visible under a simple lens. The form is transversely elongate, broad and rounded in front, and wedge-shaped posteriorly. ' The dorsal margin is peculiarly rectilinear on both sides of the beaks, a little more oblique behind than anteriorly. On the former side there is a narrow flat dorsal area reflexcd almost at right angles to the rest of the
8G THE VOYAGE OF H.M.S. CHALLENGER.
valve's surface, and consequently bounded by an acute edge extending from the umbo almost to the posterior extremity of the shell. In front there is a shallow elongate lunule, but not strongly defined. The umboncs are small, acute, and just prominent above the hinge-line. The two cardinal teeth in the right valve are about equal in size, diverge from one another, being united at the upper extremities. The anterior slopes towards the front, and the posterior in the opposite direction. The lateral grooves for the reception of the side teeth in the left valve are rather remote from the apex, and the posterior one does not extend to the umbo, being interrupted by the margin which borders the internal ligament. This is narrow, elongate, and placed in a very oblique, deep pit, subparallel with the posterior slope. The adductor scars are somewhat pyriform, the hinder one being the broader. The siphonal inflection is very deep, extending some distance beyond the middle of the valve, and is rather acuminate at the anterior extremity. The interior is glossy and indistinctly radiately substriated.
Length 15^ mm., height 9 J, diameter about 4. • Habitat. — Station 122, off Pernambuco, Brazil, at a depth of 350 fathoms ; red mud.
This is a more compressed species than Scmele (Abra) lohiUppinensis, with straighter dorsal margins, and at once distinguished by the flat posterior area.
Semele (Abra) philippinensis, n. sp. (PI. V. figs. 3-3(i).
Testa tenuis, subdiaphana albida, zonis pellucidis hie illic oruata, concentrice tenuiter striata, subsequilateralis, transversim elongata, antice rotundata, postice valde acuminata, utrinque angustissime hians. Lunula angusta, lanceolata, baud profunda. Valvarum pagina interna laevigata, superue prope umbones minute corrugata. Sinus pallii latus, profundissimus. Dentes cardinales valvse dextrse duo insequales, sinistrse tantum unus, laterales pi'ominentes, ab apicibus modice remoti.
This shell is transversely elongated, more than one and a half times as long as high, sharply rounded in front, and acuminate posteriorly. It is thin, somewhat gaping at each end, not very compressed, semitransparent, glossj^ ornamented with alternate opaque and diaphanous concentriczones, the former being the broader, and sculptured with very fine lines of growth. The dorsal outline is sul)rectilinear posteriori}^, and obliquely descending, in front being all but horizontal, feebly concave close to the beaks in the region of a small lanceolate lunule, and then faintly arcuate. The ventral margin is very broadly curved, and more ascending at the anterior than the opposite extremity. The umbones are small, a little post-median, but slightly elevated, and turned very slightly towards the front, and are nearly in contact. The two cardinal teeth in the right valve are unequal in size, diverging, and situated in front of the narrow and very oblique
REPORT ON THE LAMELLIBRANCHIATA. 87
iuternal ligament. The anterior is narrow, and diverges slightly towards the front, the posterior being twice as thick, triangular, and directed towards the opposite end. The lateral grooves are broad and deep for the reception of the raised corresponding teeth in the opposite valve. In this there is but a single cardinal, equalling in stoutness the large one in the right valve, and fitting in between it and the smaller one. The inner surface of the valves is glossy in the main, but towards the upper part it becomes dulled and roughened by a minute corrugation, granulation, and pitting. The muscular impres- sions are not clearly distinguishable, but ajipear to be moderately large. The siphonal inflection is very broad and deep, reaching far beyond the centre of the valves.
Length 16f mm., height 10, diameter 5.
Habitat. — Station 210, east of the Island of Panay, Philippine Islands, at a depth of 375 fathoms ; blue mud.
Semele (Abra) regularis, n. sp. (PI. V. figs. 4-46).
Testa elougato-ovata, tenuissima, pellucida, polita, vitrea, paulo insequilateralis, aUquanto convexa, utrinque acute rotundata, striis tenuissimis concentricis sculpta. Umbones parvi, paululum supra margincm dorsalem exerti, paulo pone medium collocati. Margo dorsi leviter convexus et declivis ; ventralis late regulariterque arcuatus. Dentes laterales valvse dextrae, elongati, lamellares, ab apice fere sequidistantes. Cardinales duo divergentes, iufequales, postico majori triangulare. Fossa ligament! angusta, elongata, profunda. Sinus pallii profuudissimus, antice late rotundatus.
Of this fragile shell only a single right valve was dredged. It is excessively thin, semitransparent, glossy, and sculptured with extremely fine lines of growi;h. It idso exhibits towards the ventral margin a few short radiating striae, which, however, may be merely accidental scratches. It is of an elongate ovate form, acutely rounded at both ends, rather convex, somewhat inequilateral, the anterior side being rather longer than the posterior. The dorsal margin is gently convex on both sides and moderately sloping, the ventral being broadly and regularly curved. The beaks are small, a little post-median, and slightly raised above the hinge-line. The two cardinal teeth of the right valve are of unequal size, diverging, the posterior being nearly twice the size of the front one, stout and triangular. The laterals are long, slender, prominent, about equi- distant from the apex, and separated from the outer edge by a deep groove. The cartilage- pit is very long, deep, and narrow. The paUial sinus is likewise very deep, broadly rounded in front, and extends about three-fourths of the total length across the valve.
Length 7 mm., height 4f, diameter of valve If.
Habitat. — Station 185b, east of Cape York, North Australia, in 155 fathoms; coral sand.
88 THE VOYAGE OF H.M.S. CHALLENGER.
Semele (Abra) longicallus (Scacclii). -"^
TeJlina longicallus, Scacclii, Notizie Concli. foss. di Gravina, itc, p. 16, \>]. i. fig. 7. Erycina longicalUs, Philippi, Euum. Mol. Sicil., vol. ii. p. 9, pi. xiii. fig. 7. Alira loiifficall is, Sars, Moll. Eeg. Arct. Norv., p. 74, pi. vi. figs. 3a-c, pi. xx. fig. 4. Syntlosmija longicalUs, Dall, Bull. Mus. Comp. Zool., Harvard College, vol. ix.. No. 2, p. 133. Scrohicularia loiigicallns, Jetfrej'S, Proo. Zool. Soo. Lond., 1881, p. 926.
Habitat. — Station 75, off the Azores, in 450 fathoms ; volcanic mud.
For the distribution of this species, which occurs in many phices, and at vastly different depths in the Atlantic, and also in a fossil state in Italy and Norway, reference should be made to the paper by Dr. Gwyn Jeffreys quoted above.
Semele [Abra) j^rofunclorum, n. sp. (PI. Y. figs. 5-56).
Testa leviter iufequilateralis, transversim ovato, postice hians valdeque acuminata, subcompressa, tenuis, subdiaphana, alba, polita, conceutrice exiliter striata, antice anguste lunulata, postice area lineare instructa. Umbones ^ arvi, acuti, paululum pone medium siti. Margo dorsalis posticus obliquissimus, subrectus, anticus prope umbones leviter concavus, deinde vix excurvatus. Dentes cardinales duo in utraque valva, valde intequales. Sulci laterales in dextra angusti, profundi, ab apice subremoti. Fossa pro ligamento angusta, elongata. Impressiones musculares insequales, antica elongata, postica rotunde pyriformis. Sinus pallii latus, profundissimus. Fascies valvarum interna plerumque polita, seel in medio, umbonesque versus minutissime subgranulata.
This sjjecies is longer than high, broadly rounded in front and ratlier acuminate at the hinder end. The shell is inequilateral, the anterior portion being rather the longer, very thin, transparent, ami moderately flat and slightly gaping posteriorly. The surface is smooth and glossy, and sculptured with fine concentric strife or lines of growth, and in addition faint indications of very unimportant radiating sculpture are traceable. The hinder dorsal slope descends very obliquely, and is almost rectilinear. The anterior margin is much more horizontal and slightly arcuate, except close to the umliones, where a faint conca\"ity is met with. The lunule is elongate, narrow, and defaced by a slight but distinct ridge on each side. The area is also narrow and defined by a sharpish ridge on each valve extending just beyond the lateral teeth. In addition to this there is a second but less acute angle on each A'alve, forming, as it were, a second larger area reaching to the posterior extremity of the shell. The beaks are small, acute, and a little elevated. The cardinal teeth are two in number in each valve. In the right the posterior is twice as large as the front one, whilst in the left it is smaller, thin, lamellar, and borders the cartilage-pit. The lateral dental grooves in the dextral valve are narrow, deep, and moderately distant from the umbo, which they do not reach on either side. The internal ligament-pit is long and narrow, and parallel
REPORT ON THE LAMELLIBRANCHIATA. 89
with the hinder slope. The interior of the valves is somewhat glossy towards the outer margins, whilst in the centre and subumhonal region it is minutely suljgranular. It is also marked with a faint radiating substriation. The anterior nmscular scar is very elongate, pyriform, and not nearly so broad as the posterior. The siphonal inflection is broad, and terminates in a sharply rounded extremity far beyond the middle of the valves. From this extremity a shallow groove extends towards the beaks, and a similar impressed ray (although insignificant) is generally ol:)servable radiating from llic uuilio to the inner margin of the posterior adductor scar.
Length 18 mm., height 12, diameter Sf. A smaller specimen is 12| long, 8^ high, and 3^ in diameter.
Habitat. — Station 85, near the Canaiy Islands; depth, 1125 fathoms. Station 73, west of the Azores; depth, 1000 fatlioms. Station 98, west of Sierra Leone, in 1750 fathoms. Station 244, Mid North Pacific, at a depth of 2900 fathoms.
Two specimens from the last locality I fail to distinguish from those from the Atlantic. They may be a little narrower and not Cjuite so acute posteriorly, but with the exception of these trifling and possibly individual peculiarities I can discover no essential specific differences. Ahra longicallus (Scacchi) closely resembles this species, but is a little narrower, not quite so acute at the posterior end, and has a shallower pallial sinus.
Semele (Theora) iridescens (Hinds) (PI. V. figs. 6-6h).
Necera iridescens, Hinds, Proc. Zool. Soc. Lond., 1843, p. 78. Theora iridescens, H. and A. Adams, Gen. Eec. Moll., vol. ii. p. 370. Theora iridescens, A. Adams, Ann. and Mag. Nat. Hist., 186-4, vol. xiii. p. 209. Theora iridescens, Tryon, Amer. Journ. Concli., vol. iv., Appendix, p. 118.
Testa tenuis, subhyalina, vitreo-alba, valde nitida, inasquilateralis, 8ec[uivalvis, utrinque anguste hians, antice lata, rotundata, postice cuneata, paulo veutricosa, incrementi lineis striata. Margo dorsi anticus primo vix arcuatus, dein oblique curvatus, posticus recte declivis. Ventris margo late arcuatus, postice leviter sinuatus. Umbones mediocriter magni, supra cardinem paulo prominentes. Denies cardinales duo ante fossam ligamenti in valva dextra coUocati, unicus in valva sinistra. Denies laterales utrinque tenues, prominentes. Fossa cartilaginis obliqua, intus recedens. Sinus paUii magnus, profundissimus. Pagina interna radiatim et confertim striata.
Length 17^ mm., height 11, diameter 8.
Habitat. — Amboina, in 15 to 20 fathoms (Challenger) ; Island of Luzon, Philippines (Hinds) ; Yobuka, Japan (A. Adams).
The above description is drawn up from the t}-pe specimens in the British Museum, as the single valve obtained by the Challenger is but immature. From this it will be seen that the details of the hinge do not correspond with the description given by Messrs.
(zool. CHALL. EXP. — PART XXXV. — 1885.) Mm 12
90 THE VOYAGE OF H.M.S. CHALLENGER.
Adams, wlio iiiakL' no meutiou of lateral teeth. These are very thin in this species, and rather close to the beaks, especially the front one. In the right valve they are separated from the dorsal line liy a narrow groove which receives the elevated marginal teeth of the opposite valve. Indeed I fail to perceive hardly any difi'erence between the genus Thcora and Abra, except that the cartilage-pit may be rather larger in most species of the former than in any forms of Ahra with which I am acquainted. The form and texture of the shell are similar in both groups, and the pallial sinus is likewise large and deep. In the Annals and Magazine of Natural History for 1864, vol. xiii. p. 208, Mr. A. Adams again characterises Theora, stating that there are no primary teeth, and in describing Theora (NecBva) fragilis (Proc. Zool. Soc. Lond., 1855, p. 226) he observes that "there are no lateral teeth." Such assertions as these show how very superficial his examination (jf the sjjecies he cites must have been, for all have true cardinals as well as lateral teeth. The subgenus Eridojolemu, which he founds on the Theora lumbrica of Gould, is not in my opinion worthy of retentioii. It differs only from other forms of Theora in possess- ing a radiating ridge or rib within tlie valves extending from the beaks obliquely towards the anterior end.
This genus (Theora) was formerly placed by the brothers Adams near NeoBva, but afterwards was removed by A. Adams to the Telliuidae, a location which is probably correct. He says " the deep sinus in the pallial line, together with the form of the valves and the pellucid vitreous texture of the shell, clearly show that this genus belongs to the Scrobiculariate division of the Tellinidse, and not very far from the Abra of Leach or Sy)idos)iii/a of Reeluz."
Family T E L l i n i n m.
Subfamily Psamjiobiin.^. Psammobia, Lamarck.
Ps^ammobia ' costulata, Turton.
Psammohia cosfulafa, Turton, Conch. Ins. Brit. Dithyra, p. 87, pi. vi. fig. 8.
Psanimohia costulata, Brown, 111. Conch. Gt. Brit., pi. xxxi.K. fig. 34.
Psammohia costulata, Philippi, Abbild., vol. i. p. 98, pi. i. figs. 3, 4.
Psammohia costulata, Keeve, Conch. Icon., vol. s. fig. 38.
Psammohia costulata, Forbes and Hanley, Brit, lloll., vol. i. p. 279, pi. xix. fig. 5.
Psammohia costulata, Jeffreys, Brit. Conch., vol. ii. p. 394, vol. v. p. 187, pi. xlii. fig. 2.
Psammohia discors, Philippi, Enum. Moll. Sicil., vol. i. p. 23, pi. iii. fig. 8.
Habitat. — Tenerife, Canary Islands, at a depth of 70 fathoms.
This species has already been recorded from these islands. It has a wide range,
' The generic name Gari of Schumacher was published iu 1817, a year previous to Lamarck's Psammobia ; the latter, however, being generally adopted, and more in accordance with the accepted notions of zoological nomenclature, should, I think, be ineferred.
REPORT ON THE LAMELLIBRANCHIATA. 91
having been met with in tlie Mediterranenn, at Madeira, and off the Norwegian and Britisli coasts.
Psammohia pidcherrima, Deshayes.
Psammohia pulchern'ma, Deshayes, Proc. Zool. Soc. Lond., 1854, p. 325. Pganmiohia pulchcrrinia, Reeve, Conch. leoii., vol. ,k. iig. 46.
Habitat. — Station 172, off Nukalofa, Tongatalju, in 18 fathoms; coral mud.
The habitat of this species lias hitherto Ijeeu unknown. The type shell tigured liy Reeve is only half-grown, and on this account has been described as " thin." The .single specimen obtained by the Challenger is probably adult, and at this age is rather a thick shell in comparison with many other species of this genus. It is 31 mm. long. 15 high, and 8^- in diameter.
It is of a yellowish tinge ornamented with several slightly arcuate .sanguineous rays, and tinted at the hinder extremity with pale rose. The interior is painted somewhat like the outside, except that the rays are rather more purplish and clouded. The valves are very slightly inequilateral, the anterior side being the shorter, but not so dispropor- tioned as represented by the figure in the Conchologia Iconica. They are transversely elongate, only half as high as long, moderately convex, having the anterior two-thirds of their surface coarsely obliquely sulcate and ridged, the ridges being broader and the intervening grooves narrower than posteriorly, where they terminate abruptly at the first of the oblique radiating costse which adorn the hinder pqrtion of the surface. These are ten in number, gradually thicken as the shell enlarges, are separated by deep furrows, and in the early stages of growth or towards the umbones are more or less nodulose. The single tooth of tlie left valve and the posterior in the right are somewhat cleft at the tip, the front one in the la