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PROCEEDINGS
OF THE GENERAL MEETINGS FOR SCIENTIFIC BUSINESS
OF THE
ZOOLOGICAL SOCIETY
OF LONDON,
L921) ppwl 446,
with 17 Puates anp 157 TEX'-FIGURES.
Looe BRARIES A
Seer ee
PRINTED FOR THE SOCIETY, SOLD AT ITS HOUSE IN REGENT’S PARK. LONDON: MESSRS. LONGMANS, GREEN, AND CO, PATERNOSTER ROW,
Pm’ i j Hi GW eee ll | - Fs Pl | v4 ¢ OF THE j | iv \
COUNCIL AND OFPFICHRS
OF THE
ZOOLOGICAL
SOCIETY
OF LONDON,
1921.
Patron. His Masesry Tur Kina, COUNCIL. His Grace Tur Duxe or Beprorp, K.G., F.R.S., President.
ALFRED H. Cocks, Hsq., M.A.
CuHaRLES DrumMonb, Esq., Treasurer.
ALFRED Ezra, Esq., O.B.E.
THe Rieur Hon.'lue Viscount Grey, KeG PC!
Sim Srpney F. Harmer, K.B.E., MAC ScD RRS ny aces President.
Pror. James P. Hitn, D.Sc., F.R.S., Vice-President.
WitiiamM Huntsman, Hsq.
Masor THe Lorp Anasrarr Roserr [nnes-KeEr,
Pror. Ernest W. MacBripe, D.Sce., F.R.S., Vice-President.
Cot. Stir Henry McManon, G.C.M.G., K.C.1.E.
E. G. B. Mrape-Watpo, Esq., Vice-President.
P. Cuatmers MircHeny, Esq., C.B.H., M.A., D.Se., LL.D., E.R.S., Secretary.
THE Har or Onstow, O.B.E.
Masor ALBerr Pam, O.B.E.
Tue Lorp QUEENBOROUGH.
His Grace THe DvKeE or Rurtann, K.G.
Masor Ricwarp 8. Taytor.
A. Trevor-Barryz, Esgq., M.A.
Anruony H. WINGFIELD, Esq., Vice-President.
A. Smita Woopwarp, Esq., LL.D., F.R.S., Vice-Pre-
sident.
PRINCIPAL OFFICERS. P. Cuaumers Mircuet, C.B.M., M.A., D.Sc., LL.D., F.RB.S.,
Secretary.
R, I. Pococx, F.R.S., F.LS., Curator of Mammals and Resident Superintendent of the Gardens.
D. Sera-Suiru, Curator of Birds and Inspector of Works.
Epwarb G. BouLencrr, Curator of Reptiles.
Miss L. KE. Cuzxsman, F.E.S., Curator of Insects.
Prof. R. 'T. Lurprr, D.Sc., M.D., Director of Prosectoriw.
Dr. C. F. Sonnvae, Ch.B., Anatomist.
Dr. N. 8. Lucas, M:B., Ch.B., Pathologist.
Dr. G. M. Vuvers, M.R.C.S., L.R.C.P., Hon. Parasitologist.
F. Martin Duncan, F.R.M.S., Librarian.
F.W. Bonn, Accountant. W. H. Coun, Chief Clerk.
LIST OF CONTENTS.
1921, pp. 1--446.
EXHIBITIONS AND NOTICES.
The Secretary. Report on the Additions to the Society’s Menagerie during the months of November and December lO One eye. cccni: Las suas atten eakie ee gas onde wer eaters
Mr. E. G. Bountenenmr, F.Z.S. Exhibition of, and remarks upon, a Black Salamander (Salamandra atra) .........
Iieots do 1, Ili, MRIS, IO /Agse 1 eb-demberanveyay oie cx remarks upon, a series of lantern-slides of the Foetus of a Three-toed Sloth (Bradypus tridactylus) .........
The Secretary. Report on the Additions to the Society’s Menagerie during the month of January, 1921 ......
Prof. G. Exuior Smiru, F.R.S., F.Z.S. Exhibition of, and remarks upon, photographs of a living example of
er sonishy 4 dalatewll: pare car. kere essnaen. 5 seks aeee te waked.
Dr. R. W. Saurevpt, C.M.Z.S. The last of the Passenger- Pigeons (Hetopistes migratorius). (Text-figure 1.) ...
Mr. R. i. Pocock, F.R.S., F.Z.S. Exhibition of, and
remarks upon, the skull of a Sumatran Tiger .........
——. Exhibition of, and remarks upon, a Cheetah skin iromeLancamVvilka, LerritOry ..-....-ses-neseoeeeee2- scree ee
The Srcrerary. Report on the Additions to the Society’s Menagerie during the month of February, 1921 ......
Dr. P. Coatmers Mrrcnrny, C.B.E., F.R.S. Exhibition a sara
of, and remarks upon, lantern-slides of a Baby Chim-
panzee born in the New York Zoological Park ......
Page
183
183
183
184
184
iv
Sir Srpney F. Harmer, K.B.E., F.R.S. Exhibition of, and remarks upon, a photograph of Elephant Twins ......
Mr. K. G. Bounencer, F.Z.8. Exhibition of Reptiles and Batrachianrs hee Mei cee me Mee cme Rein Mom epee RE ete dA
Miss L. EK. Corrsman, F.E.S, Exhibition of, and remarks upon, a nest of Anapha venata (Lepidoptera) .........
The Secretary. Report on the Additions to the Society’s Menagerie during the month of March, 1921 .........
Mr. R. H. Burne, M.A., F.Z.S8. Exhibition of, and remarks upon, a series of mounted specimens of young Flat Fish demonstrating various stages in the transference of the left eye to the right side of the head ............
Dr. P. CHatmers Mircueny, C.B.E., F.R.S. On a letter received from Mr. E. H. Bean, Director of the Wash- ington Park, Milwaukee, Wis., U.S.A., describing the successful rearing of a Polar Bear Cub ............
Mr. C, Davirs SueErporn, F.Z.8. Exhibition of a coin of the Saka Dynasty, showing the so-called ‘“ maneless Wi Ore eee ete seer ceric crete tee tants ei semtaranmtiae is Solaire Bie
Mr. F. Martin Duncan, F.Z.8. Exhibition of, and remarks upon, a series of Jantern-slides of a remarkable nest offthe Waspi(Vespaigenmanied) si, esecere see rere ae oe
Mr. D. Sera-Smirn. Exhibition of, and remarks upon, a series of skins of the Australian Budgerigar (Jelo- psittacus undulatus), showing colour-varieties that have; been produced imicaptimity: a eeeeeteerer ester scene
Major EK. E. Austex, D.S.0., F.Z.S.. On an apparent change of habitat on the part of the Common Cricket (Gryllus domestics) sane ecenne eter eee ecne eee cee ec:
Page
4-43
445
443
443
444
444
445
445
St)
whe
PAPERS.
. The Comparative Anatomy of the Tongues of the
Mammalia.—II. Family 1. Simiide. By CHaruEs F. Sonnrac, M.D., Ch.B., F.Z.S. (Anatomist to the Society) im (extateouness N92) eee cca stecceeissdecsserss on
. Note on the Capture (in London) of a rare Parasitic
Fly, Hammomyia (Hylephila) unilineata Zett. By Lt.-Col. 8S. Moncxron Copeman, F.R.S., M.D., F.Z.8.
(MexcGSimMoTMMe we Ns gargtsg settee dc ang necks demtiaeeee saree
. The Bases of Classification of the Theriodontia. By
D. M. 8. Watson, F.Z.S. (Text-figures 1-29.) ......
Experiments on Colour-Changes of the Spotted Sala- mander (Salamandra maculosa), conducted in the Society's Gardens. By E. G. Boutuncer, F.Z.S. (Curator of Reptiles). (Plates I. & II.; Text- DIC ATURE RTE) uch ea Be abi cha tad aba Meio rk ane A AN eae oe
. Contributions to the Morphology, Classification, and Zoo-
geography of Indian Oligocheta. By J. SrepHEnson, D.Sce., F.Z.S. (Lecturer in Zoology in the University omebidimbbureh) ay ((ext=tioures lia seeesee cake -.ees saacioe
. On the Structure of the Reptilian Tarsus. By R. Broom,
D.Se., F.R.S., C.M.Z.S. (Text-figures 1-27.) .........
. A Contribution to the Anatomy of the Three-toed
Sloth (Bradypus tridactylus). By CHartus F. Sonnvac, M.D., Ch.B., F.Z.S8. (Anatomist to the Society). (Plates I.-IV.; Text-figures 10-15.) ..............2005
. Report on the Deaths which occurred in the Zoological
Gardens during 1920. By N.S. Lucas, M.B., F.Z.S. GEacholooistite) tine Socleby)) eie.ce: sencecms-cs5c0scsn0ee<=
On the Reproductive Organs of the Ascidian Aiiken- thalia borealis Gottschaldt. By Dr. AueusTa ARNBACK- CHrisiie-LinpE. (Text-figures 1-8.) .........0..ecceee
(St) On
99
179
10.
ee
13.
14.
16.
10S);
v1
On the Variation of the Seapula in the Batrachian Groups Aglossa and Arcifera. By Joan B. Procter, le Ane iuarel (liven aires tfetinmenye)l-=11(0),)) V4 naaanoeescahondabriaesoon oes
Notes on Marine Wood-boring Animals. —LI. Crustacea. By Wi A © AL MEAN IDES Conte Zia neces eterinienys ee feet pees
- Colour-production in relation to the Coloured Feathers
of Birds. By A. Mattock, F.R.S., F.Z.S8. (Text- fiioumies LAAs, 55ers eee meme 9 lo leet
Fossil Bird-remains collected by Dr. Forsyth Major in Sardinia, Corsica, and Greece. By EH. T. Nrewron, Le Bi ig ie Ria Noon Gn Aion Sad ob cae AARC ERROR ABABA OD Hic
The Oriental Species of the Genus Callistomimus (Coleoptera Carabide). By H. i. ANDREWEs. (SAC rer Ey Neperte c STOEL Ce Cues nalsd an academe on Beare meee:
. On the Molluscan Genus Cochlitoma and its Anatomy,
with Remarks upon the Variation of two closely-allied Forms. By G. C. Rosson, B.A. (Text-figures 1—9.)
A Revision of the Melolonthine Beetles of the Genus Lictinohoplia. By Gade Arrow, H-Z.9.) Hanis: (dca Eth ca Bene et ES Set Mood hae on Suda pHs aa nMmr aN Ne
. The Comparative Anatomy of the Tongues of the
Mammalia.—III. Family 2. Cercopithecide : with notes on the comparative physiology of the tongues and stomachs of the Langurs. By Cuarues F. Sonntac, M.D., F.Z.S. (Anatomist to the Society). (Text-figures NOSSO) ie arte ere sseare es kites ee ene
. Descriptions of New Moths from South-Kast Brazil.
By E. Duxiyristp Jones, F.E.S., F.Z.8. (Plates AR Ie) Rane ar RE Li cn Aah dene BAUS Sor G cbt
On some new or little-known Acari, mostly Parasitic in Habit. By Sranuey Hirst, F.Z.8. (Text-figures Lie SR ON II RT RUS eee sl oie
. Observations on the Habits of Cochlitoma zebra, var.
fulgurata (Pfeitter), and Cochlitoma zebra, vay. obesa (Pfeiffer), in Confinement. By Jane Lonesrarr, Ath Depo Wh © they eon (led tain sis JESSIE) sh Soeesccodaasaeemeodabe
215
379
vil
Page 21. The External Characters and Classification of the Procyonide (Raccoons,. etc.). By R. I. Pocock, ERS eee ees a (Mext-tomres Ue Woe )i cere: entineens so 389 22. New or little-known Reptiles and Batrachians from Southern Annam (Indo-China). By Maucoim A. Smita, M.R.C.S., L.R.C.P., F.Z.8. (Plates I. & I. ; Me xt ati Ue Se Ma aM ects. eaciqnecicta sire weidec vrs veeind else A423 Alphabetical Mistroi@ontribwtorse 5. 282.Ge. acca. c.acsnecescess vill AindexqotlilllistraelOmsi, wencrfe a seieisie seciaect asec cls selac/eos Xl
TRIGGER eT RR SP Xx
ALPHABELVCAL List
OF TIE
COND RB O R's:
With References to the several Articles contributed by each.
(1921, pp. 1-446.)
AnprReEwes, H. EH. The Oriental Species of the Genus Callistomimus (Coleoptera, Carabide). (Plate I.) .......................00..
Arrow, G. J., F.Z.S., F.E.S. A Revision of the Melolonthine Beetles of the Genus IR gHoolnooliais (OBEN) Is) kackeshon0 sooo ecdnssondseagcoduseas 605
Austen, Major H. H., D.8.0., F.Z.8. On an apparent change of habitat on the part of the
Common Cricket (Gryllus domesticus) .............0.00.0ce00
Bouuencer, EH. G., F.Z.8. (Curator of Reptiles). Experiments on Colour-Changes of the Spotted Sala- mander (Salamandra maculosa) conducted in the Society's Gardens. (Plates I. & 1J.; Text-figure1.) ............... Exhibition of, and remarks upon, a Black Salamander
(Salameandre Gtr) ..occecceceenerecneeeenerecnee cee teneeteeteneees
Exhibition of Reptiles and Batrachians ................5-
Page
267
446
1x Broom, R., D.Sc., F.R.8., C.M.Z.S.
On the Structure of the Reptilian Tarsus. (Text- PUMICE Se IA he Mcrae ORRER HEA ok sehcaah Maen ASEM and ome uc ses
Burnz, R. H., M.A., F.Z.8.
Exhibition of, and remarks upon, a series of mounted specimens of young Flat Fish, demonstrating various stages in the transference of the left eye to the right side Ob ble heads. airy ears eeey ener esc San ener n sa Mn RSS dco ass
Caiman, W. T., D.Sc., F.Z.8.
Notes on Marine Wood-boring Animals.—II. Crus- LUBY GLSP Nae Bes Baia Oo rR ORE IOUS Bit HN TILE ae Rs a a ol
CurrEsMAN, Miss L. E., F.E.S.
Exhibition of, and remarks upon, a nest of Anapha WETMEGE UBPUG OP CELA) es toce ceysasctsee eas aetsaeiels aiaises are se Side
CorEmMAN, Lt.-Col. 8. Moncxton, F.R.S., M.D., F.Z.8.
Note on the Capture (in London) of a rare Parasitic Fly, Hammomyia (Hylephila) unilineata Zett. (Text- HisMmene) eee decs Savas sat Seacloshisesia eas uaniee see ee naeietisivets vie sels se
Duncan, F. Martin, F.Z.8, (Librarian to the Society).
Exhibition of, and remarks upon, a series of lantern- shdes of a remarkable nest of the Wasp (Vespa ger-
TUCILECE emer Bee IME Rene cte cian teat ce sicke Neate ste pecislascicin ts ¢ odie ss Baines
Harmer, Sir Srpney F., K.B.E., M.A., F.R.S.
Exhibition of, and remarks upon, a photograph of In) @olngiais TAINS oo Sok onendubbabdonn sd, JanbbddndesnosonecpBebaTe
Hint, Prof, J. P., F.R,S., F.Z.8. Exhibition of, and remarks upon, a series of lantern- slides of the Fetus of a Three-toed Sloth (Bradypus
PROGLCTAUILS) ee asta Vek elo. s elahesiose eiuish's e's sem erieia'sGucsesvo~ esac seers Proc. Zoou. Soc.—1921. b
Page
143
444
215
443
445
443
Hirst, Sranuey, F.Z.S. On some new or little-known Acari, mostly Parasitic in Jabit.. \Clext-fisures 115.) ieee, serene ceabasetaeeee
Jones, E. DUKINFIELD, F.E.S., F.Z.S. Descriptions of New Moths from South-East Brazil. (Plates Peavy as ius, scion epee ae cine. een ceeneeess
Linpr, Dr. Augusta ArnBACK-CHRISTIE-. On the Reproductive Organs of the Ascidian Awken- thalia borealis Gottschaldt. (Text-figures 1-8.) .........
LonestaFr, JANE, F.L.S., F.G.S. Observations on the Habits of Cochlitoma zebra, var. fulgurata (Pfeiffer), and Cochlitoma zebra, var. obesa (Pfeiffer), in Confinement. (Plates I.—III.) ...............
Lucas, N. 8., M.B., F.Z.S. (Pathologist to the Society). Report on the Deaths which occurred in the Zoological (Gree rake) Chbbeniver EPA DE aera gta oe hooncechnesescheannobsénosassanocn
Mattock, A., F.R.S., F.Z.8. Colour-production in relation to the Coloured Feathers of Birds, (s(Mext-fisures/ 1 =42)iepes scene pees crereraeerenen:
MircHevit, Dr. P. CHAumers, C.B.E., F.R.8. (Secretary to the Society).
Report on the Additions to the Society’s Menagerie during the months of November and December, 1920 .. Report on the Additions to the Society’s Menagerie during the month of January, 1921 ................2+--2+0 Report on the Additions to the Society’s Menagerie during the month of February, 1921 .....................--. Exhibition of, and remarks upon, lantern-slides of a Baby Chimpanzee born in the New York Zoological
1 ES He) gape ANTM alah Wa eR nN om aA heel at Ane nary
357
187
379
1)
183
184
xi Mivrewety, Dr. P. C. (cont.).
Report on the Additions to the Society’s Menagerie duninesthe miomthvot Marchi, VOQ | igsscuecsrcsssccecsste eyes On a letter received from Mr. EK. H. Bean, Director of the Washington Park, Milwaukee, Wis., U.S.A., describing
the successful rearing of a Polar Bear Cub ...............
Newron, E. T., F.R.S., F.Z.8. Fossil Bird-remains collected by Dr. Forsyth Major in
Mavainre, COrsicamaMOnGVSGCO siyvcanineeiiey, se css sense sisin cis ys
Procrur, Miss Joan B., F.Z.5. On the Variation of the Scapula in the Batrachian
Groups Aglossa and Arcifera. (Text-figwres 1-10.) ......
Pocock, R. I., F.R.S., F.Z.5. (Curator of Mammals).
The External Characters and Classification of the
Procyonide (Raccoons, ete.). (Text-figures 1-13.) ...... :
Exhibition of, and remarks upon, the skull of a POLAT PUTO OTE Siatarn nia, sinnaiivicsteleatatealettnateutaetalatirivle(e nila els aa fesse Exhibition of, and remarks upon, a Cheetah skin from
Mec Ay Uke MOC TNGOUV 9.) eine -siceenundeesise nts PO CREEL
Rosson, G. C., B.A.
On the Mollusean Genus Cochlitoma and its Anatomy, with Remarks upon the Variation of two closely-allied
Nbsee : Wo wife raya fi iC Horm (voxtetie ues On) i iiakartgmbeisiiieuvessce sss tauseles
SumrBory, C. Davius, I'.Z.8,
Exhibition of a coin of the Saka Dynasty, showing the
so-called *‘maneless lion” ...........-. SARS O ACO BE On OT aE CER TAG
Suureupr, Dr. R. W., C.M.Z.S. The last of the Passenger-Pigeons (/clopistes migra-
TORU (MMe RUC ER UMONL:)) wndsisbnraracsinrevenersaerva, ap ruasnn
Page
443
Add
AY)
197,
249
AAD
xu Smita, D. Seru-, F.Z.8. (Curator of Birds). Exhibition of, and remarks upon, a series of Skins
of the Australian Budgerigar (Ielopsittacus undulatus), showing colour-varieties that have been produced in
GEV OMIT cotta SoBde.c coon bbonodaduadsucnecanehabedncs das nop dns
Smitu, Prof. G. E.uiot, F.R.S., F.Z.8.
Exhibition of, and remarks upon, ‘photographs of a
livinssexamplerot Vansvus. «@llate de) «:i.jcceee tanner
Smita, Matcomm A., M.R.C.S., L.R.C.P., F.Z.S. New or little-known Reptiles and Batrachians from Southern Annam (Indo-China). ‘(Plates I. & II.; MMe xi HIG EOS Flim Wie 2g) Wp veces: br miclstster-Tociats o eisicles eio:ciionel de de stan
Sonntac, Cuarues F., M.D., Ch.B., F.Z.8. (Anatomist to the Society).
The Comparative Anatomy of the Tongues of Mam- malia.—II. Family 1. Simiide. (Text-figures 1-9.) ... A Contribution to the Anatomy of the Three-toed Sloth (Bradypus tridactylus). (Plates I.-IV.; Text- ritetbtsss) LUO IS)" © Se seeseoa serene do9)3s0n9s3eaa0H5s e008 ncoDe sansa: The Comparative Anatomy of the Tongues of Mam- malia.—II. Family 2. Cercopithecide: with notes on the comparative physiology of the tongues and stomachs of the Iuangurs. (ext-figures 16-36.) ...................0.
SrePpHEnson, J., D.Sc., F.Z.8. Contributions to the Morphology, Classification, and Zoogeography of Indian Oligocheta. (Text-figure 1.) ...
Watson, D., M.S., F.Z.S. The Bases of Classification of the Theriodontia. (Text- rigeamnasy (= 9.8)))) pn. Abb gonousunensods oapbeBensordensnconceancapresca:
Page
445
184
277
103
INDEX OF ILLUSTRATIONS,
Acanthodica frigida, Pl. I., p. 323. Adlurosaurid, Fig. 25, p. 87. Ailuropoda melanoleuca, Fig. 8, p. 405. Ailurus fulgens, Figs. 2, 3, 7, 10, 12, 13, pp. 395, 403, 408, 412, 414. Alaplena castraria, Pl. III., p. 323. Anisodes antennaria, Pl. IIT., p. 323. bizaria, Pl. IIL., p. 323. — carolina, Pl. III., p. 328. japaria, Pl. III., p. 323. paranaria, Pl. II11., p. 328. vigoraria, Pl. III., p. 323. Anthropopithecus troglodytes, Figs. 1, 2, pp. 3, 6. Anteosaurus magnificus, Fig. 28, p. 92. Apicia geminimacula, Pl. IL., p. 823. strigularia, Pl. IL., p. 323. Aplogompha castraria, Pl. I., p. 323. fumaria, Pl. I., p. 323. —— setinaria, Pl. I., p. 323. yaponaria, Pl. I., p. 328. Arctognathus, Fig. 20, p. 64. curvimola, Figs. 18, 19, pp. 61,
62. Arctops willistoni, Figs. 1-3, pp. 37- 39. Artace regalis, Pl. I., p. 323. zelina cetana, P\. I1., p. 323. hanebaria, Pl. I1., p. 825.
Bagodares castra, P|. I., p. d20. Bassaricyon alleni, Fig. 1, p. 893. sp., Figs. 3, 5, pp. 397, 401.
Proc. Zoou. Soc.—1921.
Bassariscus astutus, Figs. 1, 3, 6, 13, pp. 398, 597, 402, 414.
Boarnia nigraria, Pl. IL, p. 328.
Bombinator maximus, Fig. 6, p. 202.
Bradypus tridactylus, Pls. 1.—I[V., p. 157; Figs. 10-15, pp. 160, 164, 169, 171, 172, 174.
Broomia, Figs. 17, 18, p. 151.
Broomia perpleaa, Fig. 16, p. 151.
Bryocodia paulina, Pl. I., p. 823.
Bufo hematiticus, Fig. 1, p. 197.
Callistomimus belli, Pl. I., p. 233. cauliops, Pl. I., p. 233. chalcocephalus, Pl. I., p. 233. — coarctatus, Pl. L., p. 233. @abrewi, Pl. I., p. 288.
—— dux, Pl. L., p. 233.
—— jucundus, Pl. I., p. 283. littoralis, Pl. I., p. 283.
—— rubeilus, Pl. I., p. 233.
—— sikkimensis, Pl. I., p. 233. venustus, Pl. I., p. 233.
—— virescens, P1.I., p. 283. Callurapteryx paularia, Pl. I1., p. 323. Campatonema marginata, P1.11., p. 323 Carama incolorata, Pl. I., p. 323. Casea broilii, Fig. 9, p. 148.
Cercocebus ethiopicus, Vig. 32, p. 310. lunulatus, Fig. 33, p. 311. Cercopithecus ethiops, Fig. 22, p. 293.
—— albigularis, Fig. 20, p. 288. | —— burnetti, Fig. 18, p. 286.
c
X1V
Cercopithecus lalandit, Fig. 20, p. 288. —— mona, Figs. 19, 20, pp. 287, 288, —-— nisnas, Fig. 20, p. 288.
patas, Figs. 20, 21, pp. 288, 290. —— preusst, Fig. 17, p. 284.
sabeus, Fig. 23, p. 294.
schmidti, Fig. 20, p. 288. tantalus, Fig. 24, p. 297. Cochlitoma zebra var.
Sulgurata, Figs.
6-9, pp. 259, 260, 252; Pls. I., IIL., p. 379.
var. obesa, Figs. 1-5, 251=253, 255, 257 Pls. I -10L.,
p. 379. Craptoptera fenestraria, Pl. 11., p. 323.
Deiopeus, Fig. 22, p. 72.
—— leptocephalus, Fig. 21, p. 71. Demodex qgliricolens, Fig. 12, p. 369. talpe, Fig. 13, p. 370. Diademodon, Fig. 22, p. 72. Dibamus montanus, Fig. 2 oe 431. Dimetrodon, Fig. 22, p. 7
gigas, Big. 21, p. a Discoylessus pictus, Big, 5, p. 202.
Eariodes flavicilia, Pl. I1., p. 823. Ectinohoplia affinis, P\. I., p. 267. flavicauda, Pl. I., p. 267. inscripta, Pl. I., p. 267. — latipes, Pl. I., p. 267. mitidicauda, Pl. 1., p. 267. —— nitidiventris, Pl. 1., p. 267. oculicauda, Pl. 1., p. 267. scutellata, Pl. I., p. 267. suturalis, Pl. 1., p. 267. soror, Pl. I., p. 267. tibialis, Pl. I., p. 267. Ectopistes migratorius, Fig. 1, p. 441. Kmydopsis trigoniceps, Fig. 11, p. 149. Endothiodon ? microps, Fig. 29, p. 95. Eois lutearia, Pl. IIL, p. 823. Hosauravus copet, Big. 5, p. 147. Epiplema ornata, Pl. IL1., p. 528. rectangularia, Pl. II1., p. 823. Kuarctos americanus, Fig. 8, p. 405. Kupithecia aquanivaria, Pl, TIL, p. 323. ¢ —— cuprearia, Pl, TIL. p. 323.
pp.
INDEX OF ILLUSTRATIONS.
Feather, Diagrammatic drawing of, Fig. 1, p. 226. Fimbrios klossi, P\. 1., p. 423.
Galechirus scholizi, Fig. 12, p. 149. Gorgonops iorvus, Figs. 4-6, pp. 40-42. Gorilia gorilla, Fig. 3, p. 11.
pe es peguensis, Fig. 1, p. 428. var. angularis, Fig, 1,
var. irregularts, Fig. 1,
p. 428.
Hemalia magitaria, Pl. TIL, p. 323. — mantaria, Pl. I1T.. p. 323. ( Hylephila) Fig. 1, p. 32. Helioporus pictus, Fig. 10, p. 213. Howestia browni, Fig. 21, p. 138. Humming-Bird, Feather from gorget of, Fig. 2, p. 226. Hylobates hoolock, Figs 6,9 Fig. 8, p. 26. —— muelleri, Fig. 7, p, 24. Hymenomima nivacaria, P|. I1., p. 323. —— sinuosania, P|, I1., p. 323. Hypolepis bella, Pl. 1L., p. 828.
Hammomyia unilineata,
1)Oe ell eb
———— hen
Hyria gemmaria, Pl. TIL., p. 328.
Hyriogona montaria, Pl, ITT. p. 328.
—-— santaria, Pl. IIT., p. 328
Tsochromodes elegantaria, P\. IT., p. 328.
Jentinkia sumichrasti,
pp. 402, 414.
Figs. 6, 13,
King Bird-of-Paradise, Feather from wing of, Hig. 3, p. 226. Kiikenthalia borealis, Figs. 1-8, pp. 188-
191, 193, 194.
Larentiopsis costtplaga, Pl. IT., p. 323.
Leptotrachelus, Fig. 22, p. 72.
-—— eupachygnathus, pp. 56, 57.
Limnoscelis paludis, Fig. 4, p. 145.
Listrophorus argentinus, Fig. 10, p, 366.
—— frontalis, Fig. 10, p. 366.
Lobeza irrorata, Pl. 1., p. $23.
Lycosaurus pardalis, Fig. 17, p. 59.
—-— tigrinus, Fig, 20, p. 64.
Figs, 14, 15,
INDEX OF ILLUSTRATIONS,
Macacus fascicularis, Fig. 26, p. 302.
—— nemestrinus, Fig. 29, p. 306.
—— pileatus, Fig. 28, p. 305.
—— rhesus, Fig. 25, p. 301.
—— sinicus, Fig. 27, p. 303.
—— speciosus, Fig. 380, p. 307.
Megalophrys parva, Fig. 8, p. 205.
Megascolecine, Relationships of, Fig. p. 113.
Merocausta felinaria, Pl. 1., p. 328.
Metasiopsis proutaria, P). I1., p. 325.
Mictochroa pallidula, Pl. 1., p. 823.
—— paulata, Pl. L., p. 828.
Mixosaurus nordenskjoidi, Fig. 14, p- 150.
Moresa mona, Pl. 1., p. 328.
Mosasaurus lemonnetri, Fig. 26, p. 155.
a
Narope cingulata, Pl. 1., p. 823.
Nasua nasua, Figs. 2, 3, 4, 11, 12, 13,
pp- 3895, 397, 400, 410, 412, 414. Nedusia castra, Pl. I11., p. 323. Nephodia bonitaria, P|. I1., p. 823. —— paularia, P). IL., p. 323. Numia striqularia, Pl. U1., p. 328.
99 3238.
Oospiia altonaria, Pl. IIL., p.
Ophiacodon mirus, Fig. 8, p. 148.
Ophthalmophora TEA, p. 323.
Oxydia pallidaria, Pl. I1., p. 328.
columbaria, Te
Paleobatrachus sp.?, Fig. 2, p. 198.
Paleohatteria longicaudata, Fig. 18, p. 150.
Papio anubis, Figs. 34, 36, pp. 314, 319.
—— hamadryas, Figs. 34, 36, pp. 314, 319.
—— mormon, Fig. 36, p. 519.
—— porcarius, Fig. 35, p. 3817.
—— sphinx, Fig. 34, p. 314.
Paracomisies tristaria, Pl. IL., p. 823.
Peacock’s neck, Branches of blue fea- ther from, Fig. 4, p. 227.
Pelodytes punctatus, Fig. 7, p. 204.
Peloneustes philarchus, Fig. 25, p. 154.
Pelycosaur skulls, Fig. 21, p. 71.
Perophora thermesia, Pl. 1., p. 323.
xV Phurys fasciata, Pl. J., p, 828. Phyllomedusa bicolor, Fig. 9, p. 208 | Pipa americana, Fig. 4, p, 201. Platecarpus abruptus, Fig. 27, p. 155. Plestosaurus rugosus, Fig. 24, p. lod.
Polla acutaria, P\. 11., p. 323.
Polygrammodes eximia, P\. 1., p. 323.
Potos caudivolvulus, Figs. 1, 3, 5, 9, 12, 14, pp. 3938, 397, 401, 407, 412, 414,
Presbytes cephalopterus, Fig. 16, p. 279.
| Procolophon trigoniceps, Fig. 7, p. 147.
Procyon lotor, Figs. 1, 8, 4, 10, 12, pp. 393, 397, 400, 408, 412.
Psaliodes aurantaria, P), II1., p. 528.
Ptychopoda campinaria, Pl, III., p. 328. —— delicataria, Pl. I11., p. 323.
—— lelicaria, Pl. ITI., p. 323. terminaria, P}, II11., p. 323. Pygmephorus americanus, Fig. 15,
p. 377.
—— tarsalis, Fig. 14, p. 374.
Rana milleti, Pl. I1., p. 428. —— montivaga, Pl. I., p. 428. —— sauteri johnsi, Pl. IL., p. 4238.
| Lhinonyssus caledonicus, Fig. 1, p. 358.
—— coniventris, Figs. 6, 7, pp. 362, 363.
——- echinipes, Figs. 3, 4, p. 360.
—— neglectus, Fig. 5, p. 361.
—— waterstoni, Fig. 2, p. 858.
Rhodomena paularia, Pi. I1., p. 325.
—— santaria, Pl. IT., p. 328.
Rhodoneura oxydata, Pl. I., p. 323.
Rhophalodon ¢, Fig. 27, p. 90.
Jischeri, Fig. 26, p. 89.
Rosema pallida, Pl. I., p. 823.
Saccoploca strigaria, Pl. III., p. 323.
Salamandra maculosa, P\s. 1.-I1., p. 99; Fig. 1, p. 100.
Scincosaurus crassus, Fig. 3, p. 145.
Seymnognathus whaitsi, Figs. 7- pp. 46-49, 51, 53, 54.
Scymnosaurus watsoni, Figs. 23, 2 pp. 81, 85.
Seymouria baylorensis, Fig. 6, p. 147.
13,
XV1
Simia satyrus, Fig. 4, p. 15.
Sphenacodon ferox, Fig. 21, p. 71.
Sphenodon punctatus, Fig. 22, p. 153.
Sterosternum tumidum, Fig. 15 p. 150.
Symphalangus syndactylus, p. 18.
Tachychlora flora, P\. I11., p. 328.
Tarache parana, Pl. 1., p. 323.
Tarsius, Photographs of a living speci- men of, Pl. 1., p. 184.
Testudo sp., Fig. 28, p. 158.
Tetragonodes geminaria, Pl. IL., p. 328.
0 es Hig. 5,
INDEX OF ILLUSTRATIONS.
Trematops milleri, Fig. 1, p. 144. Trotogonia castraria, Pl. 11., p. 323.
Uranocentrodon p. 144.
senekalensis, Fig. 2,
Varanops brevirostris, Fig. 10, p. 149.
Varanosaurus acutirostris, Wig. 21, p. 71.
Xenopus levis, Fig. 3, p. 199.
Youngina capensis, Figs. 19, 20, p. 152.
INDEX.
1921.—Pages 1-446.
[New names in clarendon type.
Systematic references in italics.
(z.8.L.) indicates additions to the Society’s Menagerie. |
Acanthodica frigida, sp. u., 325.
Acanthus cannabina, 231. obscurus, 230.
—— pratensis, 230. Acarapis, gen. nov., 378. Accipiter nisus, 231. Achatinine, 264. Agalychnis moreletii, 207, Aglossa, 197.
Ailuropoda, 417, 420. melanoleuca, 392. Ailuropodide, 420. Ailurus, 420,
Sulgens, 392.
Alauda arborea ?, 229. arvensis ?, 231.
Alytes obstetricans, 203. Anapha venata, 443. Alaplena, gen. nov., 302. castrafria, sp. n., 302. . Anas boscas, 231.
Anisodes antennaria, sp. n., 349.
—— bizaria, sp. n., 343. —— carolina, sp. n., 344, —— japaria. sp. n., 344. —— paranaria, sp. n., 344. —— vigoraria, sp. n., 345. Anthropopithecus troglodytes, 2.
Proc. Zoou. Soc.—1921,
Anteosaurus magnificus, gen. et sp. n., 92.
Apicia geminimacula, sp. n., 331.
—— strigularia, sp. n., 330.
Aplogompha castraria, sp. n., 327.
-— fumaria, sp. n., 328.
—— setinaria, sp. n., 328.
—— yaponaria, sp. n., 328.
Aquila sp., 229, 231,
Areifera, 197, 201.
Arctognathus curvimola, 60.
Arctops, 73.
— willistoni, 36.
Artace regalis, sp. n., 553.
Asio accipitrinus ?, 231,
Azelina cetana, sp. n., 336.
— hanebaria, sp. n., 336.
Bagodares castra, sp. n., 332. Bassaricyon sj)., 892. Bassaricyonine, 442.
Bassariscus astutus, 392. Bassariscine, 421.
Batrachopsis melanopyga, 204. Boarmia nigraria, sp. n., 338, Bombinator igneus, 202.
maximus, 202.
d
XVI
Bombinator orientalis, 202. pachypus, 202.
Boselaphus tragocamelus (4. 8. L.), 442. Bradypus tridactylus, 157, 188. Broomia perpleaa, 150. Bryocodia paulina, sp. n., 324. Bubo ef. cinerascens, 229.
Bufo galeatus, 438.
granulosus, 209.
melanostictus, 209.
—— vulgaris, 208.
Bufonide, 208.
Caccabis rufa, 231, 232.
Calamaria pavimentata var. uni- formis, noy., 426.
Callistomimus, 233.
—— quticollis, 237, 242.
——— amabilis, 243.
ee pelili,ispams zor oek
—— cauliops, 236.
—— ceylonicus, 237, 245.
chalcocephalus, 236, 258.
chlorocephalus, 238.
— coarctatus, 237, 246.
—— d’abreui, sp. n., 237, 242.
— dicksont, 256.
—— @u x, sp..n., 237, 244.
eucharis, 237, 247.
—— humeralis, var. nov. (modes- tus), 237, 243.
——insularis, var. nov. (modes- tus), 287, 244.
—— jucundus, sp. n., 236, 239.
—— lebioides, 237.
.._— littoralis, 237, 249.
—— messii, 238.
——- modestus, 237, 248.
— nuir, 237, 244.
nilgirinus, var. nov. (Nair), 237, 240.
—— quadricolor, 247.
quadriguttatus, 238.
quadristigma vax. chalcocephalus,
236, 238.
- rubellus, 236. :
—— sikkimensis, sp. n., 286, 258.
—— subnotatus, sp. n., 206, 239,
INDEX.
Callistomimus suturalis, 2306.
—— venustus, sp. n., 236, 240.
—— virescens, sp. u., 236, 241.
——— vitalisi, sp. n., 237, 246.
—— westwoodi, 245.
-——— zunnanus, 242.
Callurapteryx paularia, sp. n., 329.
Calotes microlepis, 428.
mystaceus, 429.
Jalyptocephalus gayt, 210. Campatonema, gen. nov., 334. —— marginata, sp. n., 334. Carama incolorata, sp. n., 354. Casea broilii, 149.
Ceratophrys boie, 211. ornata, 211.
Cercocehus ethiopicus, 309. -—— lunulatus, 311. Cercopithecus ethicps, 292. burnetti, 286.
— lalandi, 298.
mond, 289. patas, 289. petaurista, 299.
—— preusst, 282.
pygerythrus, 298.
---— pyrrhonotus, 292.
— rufoviridis, 298.
— sabeus, 295.
tantalus, 296.
Cervus canadensis occidentalis (Z. 8. L), 443,
Chelura terebrans, 219.
Chiroleptis australis, 212.
Cinclus aquaticus ?, 230.
Cinnyris gutturalis (z. 8. u.), 444.
Coccothraustes vulgaris, 229.
Cochlitoina, 249.
zebra var. fulgurata, 250, 263,
379.
var. obesa, 250, 263, 379. Colobus, 282.
Coluber oxycephalus, 426.
Columba ef. livia, 229.
palumbus, 231.
Coracias cf. abyssinica, 229.
Corvus corone, 229,
INDEX.
Corvus monedula, 231.
Coturnix communis, 229, 231.
Cratoptera fenestraria, sp. n., Sol.
Cryptotis brevis, 212.
Cypselus apus, 251.
Demodex bovis, 371.
canis var. crinacei, 372. —— chiropteralis, sp. n., 367. —— gliricolens, sp. n., 368. —— melesinus, 372.
—— soricinus, 368.
—— talpe, sp. n., 370. Dendrelaphis subocularis, 426. Diademodon, 6d.
Dibamus montanus, sp. n., 431. Dichogaster, 104, 105, 110. Didymogaster, 115.
Digaster, 115.
Diplocardia, 104, 105. Discoglossus pictus, 201.
Dryophis dispar (2. 8. 1.), 444.
Eariodes bimaculata, sp. n., 330. —— flavicilia, sp. n., 530. Ectinohoplia, 267.
—— affinis, sp. n., 273.
auriventris, 267.
—— flavicauda, sp. n., 273.
—— formosa, sp. n., 269.
—— inscripta, sp. n., 269.
—— latipes, sp. n., 271.
—- nitidicauda, sp. n., 275.
—— nitidiventris, sp. n., 274. —— oculicauda, sp. n., —— scutellata, sp. n., 27 ss SOLOL Speier nls suturalis, 267.
—— tibialis, sp. n., 271. Ectopistes migratorius, 441. Hlosia bufonia, 210, Emydopsis, 149. Endothiodon, 94.
Eois lutearia, sp. n., 546. Hosauravus copet, 146. Epiplema ornata, sp. u., 300,
)
X1x
Epiplema rectangularia, sp. n., 351.
Erithacus rubecula, 230.
Eudichogaster, 103, 105.
Eupemphi«c nattereri, 209.
Eupithecia aquanivaria, sp. n., 345.
—— cuprearia, sp. n., 342.
—— Mmauvaria, sp. u., 343,
Falco tinnunculus, 231. Fimbrios klossi, gen. et sp. u., 425.
Fringilla celeos, 229, 251.
Garrulus glandarius, 231,
Gazella bennetti (2. 8. L.), 449.
—— subgutturosa (z.8.L.), 443.
Gorgognathus, 78.
Gorgonops, 74.
toruus, 39.
Gorilla gorilla, 9.
Gryllus domesticus, 446.
Gymnodactylus peguensis var. angularis, nov., 427.
—— peguensis yar. irregularis, noy. 428.
Hemalia magitaria, sp. n., 346.
mantaria, sp. n., 345.
Hammomyia (Hylephila) unilineata, 31.
Harrisina mephisto, sp. n., 356.
Heleioporus albopunctatus, 212,
pictus, 213.
Hirundo rustica, 229.
Howesia browni, 158.
Hydrocherus hydrocherus (2. 8. 449,
Hyla lichenata, 207,
maxima, 206.
Hylobates agilis, 19.
hoolock, 20.
lar, 25.
—— muellert, 22.
Hylodes fleischmanni, 211. —— lineatus, 211. —— martinicensis, 211,
XxX
Hylodes rantformis, 211.
Hylorhina silvatica, 211.
Hymenochirus boettegeri, 200.
Hymenomina nivacaria, sp. n., 33.
—— sinuosaria, sp. n., 338.
Hypolepis bella, sp. n., 341.
Hyria gemmaria, sp. n., 348.
Hyriogona montaria, sp. n., 349.
—— santaria, sp. n., 348.
Isochromodes elegantaria, sp. n., 335.
Jentinka sumichrasti, 392.
Kiikenthalia borealis, 187.
Larentiopsis, gen. nov., 339.
costiplaga, sp. n., 340.
Leptodactylus ocellatus, 211.
pentadactylus, 211.
Leptotrachelus eupachygna- thus, gen. et sp. n., 55.
Limnodynastes peronti, 211.
Limnoria lignorum, 218.
Limnoscelis paludis, 146.
Liolepsis belliana var. anna- mensis, nov., 429.
Liponyssus arabicus, sp. n., 365.
—— beriesei, sp. n., 362.
bursa, 365.
serpentium, 365.
Listrophorus argentinus, sp. n 366.
—— frontalis, sp n., 366.
Lobeza irrorata, sp. n., 326.
Lycosaurus pardalis, 58.
Lygosoma corpulentum, sg). 431.
stellatum, 431.
CS)
iV
Macacus fascicularis, 302.
——— inuius, 308,- |
INDEX.
Macacus nemestrinus, 306.
pileatus, 305.
—— rhesus, 299.
sinicus, 303.
speciosus, 307.
Macropus walabates (z. 8. L.), 444. Megalophrys fee, 206.
hasseltii var. pullus, nov., 440. —— intermedius, sp. n.. 439. longtpes, 206.
mijor, 205.
montana, 206.
parva, 205,
pelodytoides, 205.
Megascolecine, 126.
Melopsittacus undulatus, 445. Merocausta felinaria, sp. n., 327. Metasiopsis proutaria, sp. n., 349. Microhyla picta, 437.
Mictochroa pallidula, sp. n., 323. paulata, sp. n., 323.
Milvus ef. ictinus, 229. Moniligastride, 129.
Monogaster, 121.
Monopeltis capensis, 443.
Moresa mona, sp. n., 326. Mosasaurus, 155.
Motacilla lugubris P, 230.
Narope cingulata, sp. n., 354.
Nasua narica, 392.
Nasuine, 422.
Nedusia castra, sp. n., 352.
Nephodia bonitaria, sp. n., 337. —— paularia, sp. n., 337.
Notiodrilus, 116.
Nototrema marsupiatum, 207.
Numia strigularia, sp. n., 333. vyctimantis papua, 207.
Octocheting, 128.
Octochetus, 105.
Oligocheta, 112.
Oospila altonaria, sp. n., 349.
Ophiacodon mirus, 147.
Ophthalmophora sp. n., 329.
columbaria,
INDEX.
Otocorys alpestris ?, 231, Oxydia pallidaria, sp. n., 334.
Paleobatrachus, 198.
Paleohatteria longicaudata, 150.
Papio anubis, 318.
hamadryas, 314.
mormon, 320.
porcarius, 316.
sphine, 312.
Paracomistes ?, 356.
Pelobates fuscus, 204.
Pelodytes punctatus, 204.
Perissogaster, 115.
Perophora thermesia, sp. n., 353.
Phryniscus nigricans, 443.
Phurys fasciata, sp. n., 320.
Phyllomedusa bicolor, 207.
— burmeisteri, 208.
dacnicolor, 207.
Phylloscopus trochitus, 230,
Pica rustica, 231.
Pina americana, 200.
Pipide, 199.
Platecarpus, 155,
Plesiosaurus, 155.
Plionogaster, 115.
Plutellus, 112.
Polla acutaria, sp. n., 332.
Polygrammodes eximia, sp. n., 355.
Pontodrilus, 120.
Porzana parva ?, 231.
Potosine, 421.
Potos caudivolvulus, 392.
Pratincola rubetra, 230.
Presbytes, 278.
cephalopterus, 278.
entellus, 282.
Procolophon trigoniceps, 146.
Procyon lotor, 392.
Procyonide, 389, 420, 421.
Procyonine, 422.
Psaliodes aurantaria, sp. n., 342.
Pseudis paradoxa, 210.
Ptychopoda campinaria, sp. n., 347.
— delicataria, sp. n., 347.
—- lilacaria, sp. n., 347.
xxl
Ptychopoda terminaria, sp. n., 346. Pternohyla fodiens, 207.
Puffinus ef. anglorum, 229.
— cf. fulginosus, 229.
allied to chlororhynchus, 229. Pygmephorus americanus, 375.
var, Socotrensis, var. nov.,
376. — pilosus, 378. spinosus, 377. tarsalis, sp. n., 374. Pyrrhocorax graculus ?, 231. Pyrrhula ewropea, 229,
Ramiella, gen. noy., 109.
Rana graminea, 437.
milleti, sp. n., 482.
—— montivaga, sp. n., 436.
nigrovittata, 433.
—— sauteri var. johnsi, nov., 434.
Rhinonyssus caledonicus, sp. n., 357.
coniventris, 361.
echinipes, sp. n. (var. of f. neglectus?), 359.
——- levenseni, 357.
—— neglectus, sp. n., 359.
— waterstoni, sp. n., 359.
Rhodomena paularia, sp. n., 340.
—— santaria, sp. n., 341.
Rhcdoneura oxydata, sp. n., 354.
Rhopatlodon, 88.
Rosema pallida, sp. n., 326.
Ruticilla phenicurus, 230.
Saccoploca strigaria, sp. n., 3dl. Salamandra atra, 188.
maculosa, 99.
Saxicola enanthe, 230.
Scaphiopus solitarius, 203. Scincosaurus crassus, 145.
Scolopax rusticula, 232. Scymnognathus whaittsi, 44. Seymnosaurus watsont, 80.
Serinus hortulans ?, 229. Seymouria baylorensis, 146, Simia satyrus, 14. Siphonops annulatus, 443,
XX
Speleorchestes poduroides, 375. ventriosus, sp. n., 373. Spenceriella, 115, 120. Spheroma terebrans, 215. Sphenodon, 153.
Spreo bicolor (z. s. u.), 442. Sterna fluviatilis ?, 231.
Strix flammea, 232.
Sturnus?, 231.
Symphalangus syndactylus, 17.
Tachychlora flora, sp. n., 350.
Tarache parana, sp. n., 324.
Tarsius, 184.
Tayassu tajagu (2. 8..), 442.
Telmatobius jelksii, 210.
Testudo sp., 154.
—— migra, 443.
Tetragonodes geminaria, sp. n., 332.
Tetranycopsis horrida, 372.
Theriodontia, 35.
Totanus calidris ?, 231.
Trematops milleri, 144.
Trichecius brevipes, 366.
Trigaster, 104, 105.
Trigastrine, 129.
INDEX.
Trimeresurus monticola, 427. Triprion petasatus, 208.
Tropidonotus johannis, 426. Trotogonia castraria, sp. n., 333. Turdus merula, 229, 230.
musicus, 229, 230.
—— pilaris, 230,
viscivorus, 230.
Uranocentrodon senehkalensis, 144. Urside, 420.
Varanops brevirostris, 149. Varanosaurus, 65.
Vespa germanica, 445, Vultur cf. monachus, 229.
Xenopus calcaratus, 200. —— clivii, 200.
—— levis, 199.
Youngina, 151.
Zamenis moi, sp. n., 425.
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EXHIBITIONS AND NOTICES.
Page The Szcretary. Report on Additions to the Society's Menagerie during the months of November and December, 1920 183 Mr. E. G. Boutenenur, F.Z.S. Exhibition of, and remarks upon, a Black Salamander CSGIGIMOMAE QUA) bis gale o as clea eloie aiun, ech ataysier «ale = el crekele ods cojaee es eee ae 183 Prof. J. P. Hitt, F.R.S., F.Z.8. Exhibition of, and remarks upon, lantern-slides of the Feetus of a Three-toed Sloth (Bradypus tridactylus) ....ececcececececececeseee 183 The SECRETARY. Report on Additions to the Society's Menagerie during the month of Diammuatys LODN saints ses mishalnsclete esi oe 184 Prof. G. Exuror Smirn, F.R.S., F.Z.S. Exhibition of, and remarks upon, photographs of a living example of Zarsivs, (Plate 1.) 1.1... cee ce eee tee cette cn eee ees 184
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PAPERS.
1. The Comparative Anatomy of the Tongues of the Mam- malia. II. Family 1. Simiide. By Onarues F. Sonntag, M.D., Ch.B., F.Z.8., Anatomist to the Society.
[| Received October 14, 1920: Read February 8, 1921. |
(Text-figures 1-9.)
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Introduction.
Many papers dealing with the anatomy of the Anthropoid Apes contain details of the macroscopic appearances of the tongues. Most of the authors, however, have limited their accounts to the description of one or more salient features, such as the number and arrangement of the vallate papille. More attention, too, has been paid to the large Anthropoids than to
Proc. Zoou. Soc.—1921, No. I. 1
2 DR. C. F. SONNTAG ON THE ANATOMY
the Gibbons. I have referred to nearly thirty papers, and in no ease did I find a complete account of any of the Simian tongues. Even Deniker’s paper on the tongue of the Gorilla, which is the best, is incomplete, for it deals mainly with the tongue in the foetus and says little about its condition in the adult.
For the purpose of the present communication I have examined both fresh and preserved specimens in the Society’s Prosectorium and in the Museum of the Royal College of Surgeons, the specimens from the latter being indicated by the words Mus. R.C.S. Of all the tongues examined only the measurements of fresh specimens are given, for the dimensions of preserved ones are worthless. I am indebted to Professor Arthur Keith for permission to examine some of the tongues described in this and future papers.
Genus ANTHROPOPITHECUS.
THE CHIMPANZEE (A. troglodytes).
Of the three tongues examined one was fresh, one had been preserved in the Society’s Prosectorium, and one (No. J. 359.1) was preserved in the Museum of the Royal College of Surgeons. These are described respectively as specimens one, two, and three. The fresh specimen was a male from Landana, 8.W. Africa.
Several writers have stated that Traill first described the tongue of the Chimpanzee in 1821, but Traill’s paper is entitled “The Deseription of an Orang-Outan”’ (206). He certainly described an arrangement of the vallate papilla which closely resembles that of the Chimpanzee, but he expressly mentions the tongue as being that of an Orang *.
My fresh epee? has the following measurements:—Total length Srl’ Cua, Hong from the apex to the antero-median vallate papilla 6-1 om. length from that papilla to the epi- glottis 3 em.; width cote the lingual attachments of the anterior faucial pillars 4:5 cm.; width of the apex 3 cm.; thickness in the region of the antero-median vallate papilla 3°5 em.; thickness of the apex °3 cm.
The tongue is long and comparatively narrow, and its width does not decrease greatly from base to apex. Cunningham (118) is the only author who points out that its elongated form is due to the shape of the mouth. He also shows how the tongues of the Chimpanzee and Gibbons differ more from that of Man in the disproportion between length and breadth than does the tongue of the Orang-Outan.
The antero-median vallate papilla stands a short distance behind the summit of an elevation whence the dorsum slopes towards base and apex, but the declivity is greater in the latter direction (text-fig. 1 B, d). In this connection the Climpanzee
* Flower states that Traill really described a Chimpanzee from the Gaboon,
3
OF THE TONGUES OF THE MAMMALIA. 3
is pre-eminent among the Anthropoids, but the degree of slope varies in different individuals.
The Apex and Lateral Borders exhibit characters which are common to many of the Anthropoids. The apex is blunt and may or may not possess a median notch ; the notch only occurred
-Text-figure 1.
af k. .The tongue of Anthropopithecus troglodytes. A, dorsum; B. lateral view; C. inferior surface; D. vertical section of the side of the tongue. Descriptions in text.
in my fresh specimen. It is roughened by conical papille and tuberculated by large prominent fungiform papille. Their size varies in different tongues, but they are always numerous ; some
are smooth, glistening, and hemispherical, others are granular tee
4 DR. C. F. SONNTAG ON THE ANATOMY
and hemispherical, and others may possess a central boss (text- fig, 2A, J, m, n). All the conical papille have their points directed backwards. The lateral borders are full and rounded (text-fig. 1 D, a); they are beset with both conical and fungi- form papille, and the lateral organs are situated at their posterior extremities (text-fig. 1 B, g).
Mesial Sulci.—Mesial sulci may be present on the dorsal and inferior surfaces. In my fresh specimen (text-fig. 1 A) the median dorsal sulcus extends from the apical notch to a point 4 mm. in front of the antero-median vallate papilla. It is irregular and invaded by both conical and fungiform papille ; posteriorly it is deep and lodges fungiform papillae alone. On the base of the tongue the median row of vallate papille is situated on a depressed band of mucosa which is bounded by large papillae and lymphoid nodules.
In my second specimen there is, instead of a median sulcus, a row of prominent fungiform papille, and the only representative of the fissure is a small pit, lodging a fungiform papilla, lying immediately in front of the antero-median vallate papilla.
In my third specimen (No. J. 359.1, Mus. R.C.S.) there is neither a median sulcus nor a median row of fungitorm papille, but there is a pit in front of the antero-median vallate papilla.
The small pit described above inust not be mistaken for the JSoramen cecum of Morgagni which is absent in the Chimpanzee.
The median ventral sulcus will be described later.
Transverse ridges and sulci are absent.
The Papille.
Papille are present on the entire dorsum, apex, lateral borders, and a bounding zone on the inferior surface. This general distri- bution 1S SO common among the Anthropoids that it can be regarded as the rule. The only exceptions are the Orang-Outan and the Siamang Gibbon, which have areas on the base which are devoid of papilla. I am unable to say whether these smooth areas exist in all Siamangs, but they are not present in all Orangs.
The Circumvallate Papille (text-fig, 1 B, c & d).
The vallate papille vary in number and arrangement in dif- ferent individuals, but the relation between the species of Chimpanzee and the papillary pattern has not been stated by authors. The following types have been described :—
T-form: Flower (28); Dwight (123); Symington (202);
Huxley and Hunter.
Y-form: Gratiolet and Alix (131); Bischoff (7); Miinch [1].
V-form: Cavanna (109); Ehlers (23).
Cruciate form : Mayer (162).
Linear type: Humphry (142).
The numbers of vallate papille vary from three, as recorded by Wyman (215), to fifteen mentioned by Humphry (142).
OF THE TONGUES OF THE MAMMALIA, 5
In my three specimens the arrangements are as follows :-—
Specimen No, 1.—There are eight papille arranged in the Y-form (text-figs. 1A & 2B). Each lateral limb has an outer compound and an inner simple papilla, and the mesial antero-posterior row consists of four simple elements.
The papillary bodies of the compound papille are oval on plan ; the inner papille of the lateral rows are circular; the antero- median papilla is cireular, and the other three papille are oval on plan. All the papille are conical on elevation (text-figs. 2 A,r, & 1B, c), the narrow ends of the cones being attached to the bottom of the fosse. The surfaces are all granulated, possibly by secondary papille. The vallums are lobulated, and the fosse are more or less patulous (text-fig. 2, p, q, ¢).
Specimen No. 2.—There are eight papille arranged in the Y-form, and all of them are simple (text-fig. 2 B), The left lateral row has three papillee, the right lateral limb has two, and the mesial antero-posterior limb has three. All the papille of the lateral limbs are circular and prominent, and the vallums and fosse are well marked. They are surrounded by papillose ridges passing inwards from the corresponding lateral organs. The median row of papille consists of oval elements well recessed beneath their vallums. The most posterior papilla is difficult to see unless the pedunculated papille of the base of the tongue are withdrawn from over it.
In Specimen No. 3 the arrangement of the vallate papilla is uncommon. There are eight papille in the Y-form (text-fig. 2 B), but the two lateral limbs lie closely side by side, and the vertical limb has one papilla. The left lateral limb has four papille and the right one has three.
The Fungiform Papille (text-figs. 1 B, 6, & 2 A, m, n, 0).
Fungiform papille are numerous and cover the dorsum, apex, lateral borders, and a bounding zone on the inferior surface. They have the usual arrangement in clusters behind the apex, transverse rows farther back, and oblique chains in front of the vallate papille. On the lateral borders they are arranged verti- cally, and on the inferior surface they are in straight lines passing from without inwards.
They invade the median dorsal sulcus, and may replace it altogether. In one of my specimens there is a well-marked median row of prominent fungiform papille im place of the median sulcus.
In one of my specimens there are more fungiform papille than those presented to the naked eye, for the lens “shows how filiform papille entirely conceal many fungiforms.
At the base of the tongue (text- -fig. | A) there are many long pedunculated papille which belong to “both fungiform and conical groups. It is only possible, however, to settle by microscopic examination to which of them any particular papilla can be referred, They vary in degree of development in different
6 DR. C. F. SONNTAG ON THE ANATOMY
tongues, and I agree with Humphry (142) that some of them may be a quarter of an inch long.
These pedunculated papille are smaller and fewer than in the Gorilla, and larger and more numerous than in the Gibbons. They are absent altogether in the Orang-Outan. Their surfaces are smooth or granular. The different forms of papille are shown in text-fig. 2A, m-o.
Text-figure 2.
The papille and lateral organs of Anthropopithecus troglodytes.
a-l, conical papille ; im-o, fungiform papillex ; p—w, circumvallate papille : AA’, lateral organ; the three figures on the left side of the bottom row are vallate patterns, described in the text as 2 B.
The Conical Papille (text-fig. 1 B, a, e, & f).
The conical papille have the same form of arrangement as the fungiforms, and they are seen to the best advantage when the tongue is allowed to dry, for they then stand up on the surface. All their points are directed backwards.
They increase in size from before backwards, and from without inwards, the largest ones on the anterior part of the dorsum being in and around the median sulcus. They overlap the fungi- form papille and conceal some of them entirely. In one of my specimens they stand on ridges like those on the finger-tips.
They belong to both cylindrical and filiform groups. The filiform varieties have one or more points. When there is only one the papilla is tapering, and cireular on section. When
OF THE TONGUES OF 'THE MAMMALIA, 7
there are more than one point the body may be cylindrical, or flat and thin (text-fig. 2 A, ag). The cylindrical types ave interspersed among the others. They have a granular surface, and some of them are very rough. In the latter case, however, it is difficult to be precise as to their character; they may have lost. long points as the result of handling (text-fig. 2 A, h, ¢).
The relative proportions of the filiform and cylindrical types differ in different tongues. Hither type may be in excess, and they may in some cases be evenly distributed, but it is usual to find one form predominating.
The different forms are shown highly magnified in text- fiy. 2 A, nos. al.
Lymphoid Tissue.
The base of the tongue contains much lymphoid tissue which gives the surface a iopnleted appearance, and there is a great contrast between it and the rough anterior surface when the tongue is viewed from the side (text- fig. 1B). The degree of contrast depends greatly on the areal of filiform papille on the anterior two-thirds of the dorsum; when these are very numerous the roughness is greater and the contrast more marked.
The lymphoid nodules vary in size, and the large ones have small central pits, but it is only possible to tell by microscopic examination whether any one orifice has ducts of glands con- nected to it or not. Few of the pitted follicles lie anterior to the most posterior vallate papilla.
The Lateral Organs (text-figs. 1 B, g, & 2, AA’).
Boulart and Pilliet [2] have stated that the lateral organs of the Anthropoid Apes are well developed, and mention that the Chimpanzee has twelve ridges in its organs, but they do not say whether both organs ave the same number of fissures and ridges. Dwight (123) showed that each organ is convex in- ternally. I agree with Dwight, but not with Boulart and Pilliet. All my specimens have organs convex inwardly, but there is great varinbility in the number of fissures and ridges as the following figures show :—
Specimen | (text-fig. 2, AA’). . Right organ: Length 1:55 cm. Ridges 15. Suter 16. Left organ: Length 1:6 cm. ftidges 14. Suter 15. Specimen 2. Right organ: Length 1:4 cm. Ridges 7. Sulci 8. Left organ: Length 1:7 cm. Ridges 9. Sulet 10. Specimen 3. Right organ : — Ridges 10. Suleti 11. Left organ : — Ridges 9. Suler 10.
Each organ begins anteriorly as a number of sulci on the infero-lateral aspect of the tongue, but the pieces of the tongue
8 DR. C. F. SONNTAG ON THE ANATOMY
between them are not raised above the general surface. Behind these the ridges appear and increase both in length and pro- minence till a point is reached almost level with the outermost vallate papilla of the corresponding lateralrow. After that they diminish in size, but increase in prominence till the posterior limit of the organ is reached. Many ridges are simple, but a few are divided by small secondary sulci.
Ridges pass across the dorsum from the upper ends of the ridges of the lateral organs. These either encircle the vallate papillee or pass backwards on their outer side.
The Inferior Surface (text-fig. 1 C & 1 B, 2).
The inferior surface presents for examination a mesial sulcus, two plice fimbriatv, the papillary border, frenum and sublingual fold, or frenal lamella, so called by Pocock (text-fig. 1 B, ’, & I OS2)y
The mesial sulcus (text-fig. 1C, a) extends backwards from the posterior border of the papillary zone to the attachment of the frenum. It is not occupied by any crest as in the Gorilla.
The plice jfimbriate (text-fig. 1 C, c) are, it is acknowledged, remnants of the sublingua of the Prosimiew, and in one of my specimens the two plice and intervening piece of mucous mem- brane have the appearance of an under tongue.
The plice are two longitudinal folds, almost touching in front, running backwards and outwards from near the apex to a point well behind the middle of the tongue, but in one of my specimens they are nearly parallel to one another. They le on the lateral aspects of the inferior surface between the mesial sulcus and the edges of the tongue. Each one has undulating and crenated edges, and increases in width from before backwards.
When a vertical section of the tongue is made about its centre (text-fig. 1 D) one sees the mucosa of the floor of the mouth (@) reflected to form the frenal lamella (c). From the upper surface of the latter it is reflected on to the plica (6), and thence to the under surface of the tongue (a). The mucosa between the plica fimbriate and the sublingual fold is thrown into many small folds.
The Sublingual Fold (text-fig. 1 C, e).
The sublingual fold, or frenal lamella (Pocock), lodges Wharton’s Ducts. It is triangular in shape with the base behind. The apex is bifid and the two ducts open on the points which are very sharp; the edges are undulating and crenated. Its mucosa is continuous with that of the floor of the mouth below and the frenum linguz above.
Some have said that the sublingual fold corresponds to the sublingua of the Prosimiz, but most anatomists are agreed that the plicee fimbriate represent it, so the tongue of the Chimpanzee, which possesses both, is sufficient to disprove the statements of the former group of observers.
OF THE TONGUES OF THE MAMMALIA. 9
The Papillary Border (text-fig. 1 C, 6).
The narrew papillary border has fungiform and conical papille, the latter belonging to the filiform and cylindrical groups. They are arranged in lines passing from without in- wards. The fungiform papillae are small and most numerous beneath the apex of the tongue.
The Frenum Lingue (text-fig. 1 C, d).
The frenum is short and thick. It runs from the upper surface of the sublingual fold to the under surface of the tongue from the posterior end of the median ventral sulcus backwards.
No lytia is present in the interior of the tongue.
When the apex is examined histologically, no Apical Gland of Nuhn is seen. In this connection it agrees with the Gorilla and Gibbons, and differs from Man and the Orang-Outan.
There is only a narrow groove between the base of the tongue and the epiglottis (text-fig. 1 B, /).
Genus GORILLA. THE GorILLA (G. gorilla).
The literature containing details of the structure of the tongue of the Gorilla is not so large as that dealing with the tongue of the Chimpanzee, but the papers are more complete. Ehlers (23), Bischoff (7), and Duvernoy (22) have written accounts of the adult tongue, and Deniker (17) has described the foetal tongue very fully, but he has said little about the adult form. ‘Boulart and Pillet [2] have not mentioned the Gorilla in their study of the lateral organs of the Mammalia. The specimen which | examined (No. J. 358.1, Mus. R.C:S.) exhibits features which have not been mentioned by these authors, or are different from the conditions described by them.
The tongue has not such a great disproportion between its length and width as that of the Chimpanzee. It is comparatively broad, and in this connection I agree with Bischoff (7), and - differ from Duvernoy (22) who said it is narrow. The whole organ appears rectangular. It slopes gently from the vallate papillary region to the apex, and more steeply from the vallate region to the epiglottis; it differs, therefore, from the tongue of the Chimpanzee.
The apex is square-cut, has no mesial notch, and bears conical and fungiform papillae which are thickly clustered; the latter are not so prominent as in the Chimpanzee, but are more marked than in the Orang-Outan.
The lateral borders have large and medium-sized fungitorm and conical papille arranged in vertical lines, and they are fissured by numerous sulci prolonged on to them from the dorsum. At their posterior extremities one sees the outer ends of the fissures and Jamine of the lateral organs. In this respect the tongue agrees with that of the Orang-Outan, and differs from those of
10 DR. C. F, SONNTAG ON THE ANATOMY
the Chimpanzee and Gibbons, in which most of the lateral organs lie on the lateral borders of the tongue.
Mesial Sulci.—Mesial sulci are present on the dorsal and inferior surfaces. The dorsal sulcus lies in the centre of the anterior two-thirds ; it 1s wide and shallow, and contains many conical and few fungiform papille. Just in front of the antero- median vallate papilla there is a small pit containing both conical and fungiform papilla, but this must be regarded as a part of the mesial sulcus. It must not be mistaken for a foramen cecum, which does not exist in the Gorilla. There is no median suleus on the base of the tongue.
The median ventral sulcus (text-fig. 3 B, c) begins in front at the posterior edge of the papillary zone and runs back, widening as it goes, till it terminates in a triangular pit into which the frenum passes. It lodges a median fold of mucous membrane termed the plica mediana or mesial crest (text-fig. 3 B, d).
Transverse Ridges and Sulci.cSeveral transverse ridges and sulci are present on the anterior two-thirds of the dorsum. They are undulating and irregular in direction, and some of them cut the lateral borders of the tongue and run inwards on the bounding papillary zone of the inferior surface. The sulci are narrow and the ridges are covered with papille.
In the interior of the tongue there are neither lytta nor Apical Gland of Nuhn.
The Papille.
Papille are present on the entire dorsum, apex, lateral borders, and a bounding zone on the inferior surface. The last is better developed than in the Chimpanzee and Orang-Outan.
The Circumvallate Papille (text-figs. 3 A & 3 D, a, 6).
In my specimen there are seven vallate papille arranged i the form of a Y, and the notable feature is that most of them are compound. Each lateral limb has two papille and the median one has three.
The two papille of the right lmb are compound (text- fig. 3 D, a) and lie very close together, for their vallums are only separated from one another bya narrow fissure. Both fossee and vallums are prominent and the papillary elements are recessed below the vallums. The papillary bodies are granulated, possibly as the result of secondary processes.
The outer papilla of the left lateral limb (text-fig. 3 D, 6) is compound and the inner one is simple. The fosse are patulous and the two vallums are in continuity. It seems as if the mner papilla is an element which has been separated off from the outer compound papilla. In the case of the compound papilla the elements are recessed below the vallum, but the simple papilla is more prominent. The surfaces of the elements are granular.
The outer papille of the lateral limbs are level with the
OF THE TONGUES OF THE MAMMALIA. Wy
Text-figure 3.
° ' ON Mp
Zs ty ; Se ae
The tongue of Gorilla gorilla.
A. dorsum; B. inferior surface ; C. lateral view; D. a, 6, d, e, papilla; D. ¢, Jateral organ showing the lateral vallate papilla above its posterior laminz.
12 DR. C. F. SONNTAG ON THE ANATOMY
posterior extremities of the lateral organs as in the Orang-Outan (text-figs. 3A & 3D, c). In the Chimpanzee and Gibbons, on the other hand, they are level with the central rows and sulei of the lateral organs.
The median row of vallate papille has three elements. The anterior and posterior ones are simple, but the middle one is compound.
The following numbers and arrangements have been re- corded :—
1. Five papille in V-formation—Ehlers (23).
2. Five papille in V-formation in the feetus—Deniker (17). 3. Six papille in V-formation—Duvernoy (22).
4, Seven papille in V-formation-—Bischoff (7).
5. Hight papille in V-formation—Duvernoy (22).
My specimen, therefore, differs in the type of arrangement of its vallate papillee from that described by other authors.
The Conical Papille.
The conical papille have the same forms and arrangements as in the Chimpanzee, but they are not so large in the anterior two- thirds of the dorsum. Behind the vallate region, however, the large pedunculated papille are larger and much more numerous than in the Chimpanzee. These latter papille are tapering or club-shaped, and many of them have small secondary processes as described and figured by Bischoff (7). Their points are directed backwards, and some of them overlap the most posterior vallate papilla (text-fig. 3 D, e).
The Fungiform Papille.
The fungiform papille are not so large or so numerous as in the Chimpanzee, but they exceed those of the Orang-Outan both in size and numbers. They are in clusters behind the apex, in transverse rows farther back, and in oblique chains in front of the vallate papille. They are most numerous behind the apex and close to the lateral borders of the tongue, and diminish in numbers towards the mesial suleus. There are, however, po fungiform papille overhung by filiform types.
When the tongue is viewed laterally (text-fig. 3 C, FP) one sees how prominent many of the fungiform papille are, and some of them appear almost pedunculated. In this connection the Gorilla differs from all the other Anthropoids.
On the sides of the tongue the fungiform papille are in vertical chains, and they are in rows passing from without inwards on the inferior surface (text-fig. 3 C, /'P).
The Lateral Organs (text-fig. 3C, LO, & 3 D, c). The lateral organs of the Gorilla have been omitted from Boulart and Pilhet’s paper. They are situated on the edges of the dorsum of the tongue, beginning posteriorly on a level with
OF THE TONGUES OF THE MAMMALIA. he
the external vallate papille of the lateral rows, and extending forwards to a point level with the posterior extremity of the mesial suleus. The numbers of ridges and elevations are as follows :—
Right organ: Length 1-3 em. Ridges 11. Sulci 12. Left organ : Length 1°35 em. Ridges 12. Suler 13.
In his study of the tongue of the fcetal Gorilla, Deniker (17) has shown that the lateral organs are better developed than in the adult.
The ridges and sulci just cut the lateral borders of the tongue. They are long, narrow, and tapering ; some are twisted and some have secondary fissures.
The Inferior Surface (text-fig. 3 B).
The inferior surface presents for examination a papillary border, a frenum, a sublingual fold, two plice fimbriatee, a mesial crest, and a mesial suleus which has already been described. It has, therefore, the same structures as the tongue of the Chim-
anzee, with the mesial crest in addition.
The papillary border maintains the same width across the under surface of the apex, but it widens out from before backwards along the lateral borders. It bears conical and fungiform papille whose method of disposition is of the usual type (text-fig. 3 B, a).
The most notable feature is a row of closety-set club-shaped conical papille bounding the zone internally (text-fig. 3 B, /). They increase in size from before backwards, and they he flat against the surface of the tongue. Some are entire and others are subdivided into lobules as shown in text-fig. 3 D,d. In no other Anthropoid tongue is there a uniform row of these papille.
The mesial crest, ov plica mediana, is a fold of mucous mem- brane occupying the ventral mesial sulcus (text-fig. 3B, d). It runs along the anterior border of the frenum, and thins out and disappears on the dorsal surface of the sublingual fold. Deniker (17) considers that it is a remnant of the sublingua of the Prosimie.
The plice fimbriate (text-fig. 3B, 6) are united anteriorly at the posterior border of the papillary zone on the inferior surface. When they are traced backwards they diverge and become wider and more prominent. They have undulating free margins, and ave pale in colour, The mucosa between them is pale and the vemainder is pink in preserved specimens, so the plicx and inter- vening part together look like a sublingua. A vertical section of the tongue of the Gorilla resembles that of the Chimpanzee (text-fig. 1 D).
The frenal lamella, or sublingual fold, is triangular in shape and has a rounded entire apex (text-fig. 3B, gy). Wharton’s Duets open on its dorsal surface, and the bristles shown in text-fig. 3 B, e, pass into them,
14 DR. C. F. SONNTAG ON THE ANATOMY
Bischoff (7) denied the existence of a frenum, but Ehlers (23) and Deniker (17) saw one. In my specimen it runs from the dorsal surface of the sublingual fold to a triangular depression on the inferior surface of the tongue (text-fig. 3 B).
Genus SIMIA.
THe Orane-Ouran (S. satyrus).
The tongue of the Orang-Outan resembles that of Man in its relative proportions of length and width and certain of its struc- tural peculiarities. J examined three preserved specimens in the Museum of the Royal College of Surgeons, and the following description refers to No. J.421.3. It is designated as specimen No. 1 here.
The apex is rounded, has no mesial notch, and possesses conical and fungiform papille, but both forms are small.
The lateral borders are massive, and have both conical and fungiform papille distributed in the usual manner. Only the outer ends of the lamine and sulci of the lateral organs cut the lateral borders of the tongue.
The dorsum has no median or transverse sulci.
The Papille. Papille cover most of the dorsum, apex, lateral borders, and a bounding zone on the inferior surface.
The Circumvallate Papille. The following numbers and arrangements of the vallate panillee have been recorded :—
1. Ten papille in V-formation—Flower (28), Boulart and Pilliet [2].
2. Hight papillae in V-formation—Miinch [1].
3. Seven papille in V-formation—Sandifort (271).
4, Three papille on each limb of a V—Fick (255).
5. Hight papille in the T-form—Traill (206) *.
I observed the following numbers and arrangements of the papillee :—
Specimen No. 1. (text-fig. 4 A).—The papille are arranged in the V-form, but the angle embraced by the two limbs is more acute than in Man. ‘There is an apical papilla and three papille on each limh, the whole series standing on a raised smooth band of tongue. The papille of the left limb are all simple, and the most external one has a small umbilicus (text-fig. 4A). The most external papilla of the right limb is simple, and the middle and inner papille are compound. The apical papilla is com- pound. All the papillary bodies are round or oval on plan and conical on elevation, with the free broad end of the cone over- lapping the vallum. The fossz are well marked.
* See footnote on page 2.
OF THE TONGUES OF THE MAMMALIA. 1)
Specimen No. 2.—The papille which are twelve in number, are arranged in the form of a V, but they do not stand on a raised band of tongue as in specimen number one. Several of them are compound.
Text-figure 4.
Cc
The tongue of Simia satyrus.
A. dorsum; B. ventral surface. The mucosa has been dissected back to show Wharton’s Ducts; the arrows point to the actual positions of the sublingual glands, and the dotted lines indicate the positions of the plicee fimbriate.
The Fungiform Papille.
The fungiform papille are very small. They have the same arrangement in clusters and rows as occurs in the Chimpanzee and Gorilla. In the centre of the dorsum they are concealed by long filiform papille. On the inferior surface of the tongue they are larger than on the dorsum, and they are disposed in lines passing from without inwards. A double row forms a prominent arch round the anterior extremity of the frenum (text-fig. 4 B).
The Conical Papille.
The conical papille are marked features on the anterior two- thirds of the dorsum (text-fig. 4), but they are more pronounced in some individuals thanin others. They have the same arrange- ment in clusters, transverse rows, and oblique chains as in the other Anthropoids, and they increase in size from before back- wards and without inwards. They are very long on an area in
16 DR. C. F. SONNTAG ON THE ANATOMY
the centre of the anterior two-thirds of the dorsum, but, as their points face in all directions, they appear tangled and without any definite method of arrangement. In that central area, again, fungiform papille are concealed by the conical forms. There is, therefore, a similarity to the condition already described in the Chimpanzee, and shown in text-fig. 1 A, but the papille are more diffused in the latter.
The papille belong to the filiform and cylindrical types, but the former predominate, thereby giving the dorsum its shaggy appearance.
The base of the tongue is devoid of the long conical papille which are present in the other Anthropoids, and it resembles that of Man in this respect.
On the sides of the tongue they are in vertical chains, and on the inferior surface they are in lines passing from without inwards.
In all situations, except on the central area of the dorsum described above, the points are directed backwards.
The Lateral Organs.
Boulart and Pilliet [2] state that the lateral organs have each twelve lamine, but I found that the numbers of fissures and ridges differ on the two sides as follows :—
Right organ: Length 16cm. Ridges 14. Sulei 15. Left organ : Length \-6em. Ridges 12. Sule 13.
The ridges run obliquely from below upwards, and they diminish in size both forwards and backwards, but the organs are continued by simple folds of the mucosa.
The lateral organs end posteriorly on a level with the most external vallate papilla. The greater part of each lies on the dorsum as in the Gorilla, but some of the anterior lamine and sulci project considerably on to the lateral borders of the tongue,
Lymphoid and Glandular Tissue.
The Orang-Outan agrees with Man and differs from all other Anthropoids in the possession of the Apical Gland of Nuhn. Mucous and serous glands occur as usual on the base of the tongue, but there are no large follicles with central pits as in Man and the Chimpanzee.
On the inferior surface there are several small pits surrounded by a raised zone (text-fig. 4 B), but histological examination alone will reveal their true nature. J have been unable to study these as my specimens have been preserved too iong in formalin for satisfactory histological work.
The frenum lingue is well-marked, as in Man, the plice Jimbriate are of no greater development, and the frenal lamella is as in the human tongue; it is not a triangular process as
OF THE TONGUES OF THE MAMMALIA. 17
in the other Anthropoids, but simply a fold over Wharton’s Ducts.
The tongue of the Orang-Outan, therefore, resembles that of Man in the following particulars :—
. Its general proportions.
. Its rounded apex.
. The V-type of vallate papille.
. The absence of long conical papille on the base. . The frenum lingue.
. The small proportions of the fimbriate plice.
. The nature of the sublingual fold.
. It has an Apical Gland of Nubhn or Blandin.
CO NI Oo Ol H Oo DO
In all these particulars it differs from the Chimpanzee and Gorilla, so it must be placed next to that of Man in a classifica- tion of tongues.
SYMPHATANGUS. THE SIAMANG (S. syndactylus). (Specimen No. J. 357.3, Mus. R.C.S.)
The tongue is long and narrow, and the distance between the antero-median valiate papilla and the epiglottis is long (text- fig. 5).
The apex is rounded and devoid of a notch. It bears conical and fungiform papille which have the usual disposition.
The lateral borders are full and rounded. They bear conical papille with backwardly-directed points, prominent fungiform papille, and the chief parts of the lateral organs. This condition is present in all Gibbons, but the fungiform papille vary in size and prominence in different species.
Mesial and transverse sulci are absent on the anterior two- thirds of the dorsum. Both are present on the base of the tongue, but these may have been induced by the preserving fluid.
The mesial ventral sulcus begins at the posterior border of the papillary zone, and runs backwards to open into a triangular depression into which the frenum passes.
The Papille.
Papillz are present on the apex, lateral borders, the entire anterior two-thirds of the dorsum, the sides of the posterior third of the dorsum, and the hounding zone on the inferior surface.
On the posterior third of the dorsum there is a large central area devoid of papille (text-fig. 5). It stretches forwards anterior to the median row of vallate papille, and sends out limbs on which the lateral papille stand. It extends right back to the epiglottis, and is ridged and furrowed at its posterior part. Anteriorly it is bounded by small conical papille, and large
Proc. Zoou. Soc.— 1921, No. I]. 2
18 DR. C. F. SONNTAG ON THE ANATOMY
conical papillae oceupy the spaces between its lateral borders and the edges of the tongue.
The Orang-Outan is the only other Anthropoid which has a bare area (text. fig. 4 A), but itis V-shaped and smaller in size.
The Circumvallate Papille.
Five vallate papillz are arranged in the form of a Y ; of these, three form a mesial row, and there is a right lateral and ai left lateral papilla. All the papille are circular on plan and conical on elevation, and the fossa are well-marked. But the vallums are not demarcated off from the smooth area on which the papille stand. All have smooth bodies, and the right and left lateral ones are umbilicated.
Text-figure 5.
The tongue of Symphatangus syndactylus, showing the dorsum, inferior surface, and right lateral organ with lateral vallate papilla.
The Fungiform Papille.
The fungiform papille are present over the anterior two-thirds of the dorsum except for a zone along the mid-line. They have the usual distribution in clusters and rows, and are never very large nor concealed by conical ,papille. On the lateral borders and inferior surface they are arranged in lines running vertically or from without inwards.
The Conical Papille.
They have the usual form of distribution in clusters and ridges, and their characters are visible to the naked eye right forward to the apex. Most of them are filiform with the points eine cid backwards, or backwards and inwards.
OF THE TONGUES OF THE MAMMALIA. 19
The conical papillee on the base increase in size from before backwards, but they never attain the degree of development which is exhibited on the tongues of the Chimpanzee or Gorilla. They belong to the cylindrical type, and many of the large ones at the base have long hair-like processes. These basal papille are arranged in two groups—one on each side of the non- papillary area.
No foramen cecum, lytta, or plice fimbriate are present.
The Lateral Organs (text-fig. 5). The two lateral organs, which are convex inwardly, have the following measurements, etc. :—
Right organ: Length1-3em. Ridges 11. Sulei 12. Left organ : Length 13cm. Ridges 12. — Sulet 13.
The organs are situated chiefly on the sides of the tongue, but the inner extremities of their laminze and sulci extend on to the dorsum. Anteriorly and posteriorly they are continued by simple folds of mucous membrane. These characters are common to all the Gibbons and the Chimpanzee.
The lateral vallate papillze are level with the lamine and ridges of the posterior halves of the organs, but they are not so far back as in the Gorilla or Orang-Outan, and not so far forwards as in the Chimpanzee and many other Gibbons.
There are no lymphoid nodules with central pits on the base of the tongue.
The frenwm is short,and runs from the floor of the mouth to a triangular depression on the inferior surface of the tongue.
The Siamang is the only Gibbon which has no bifid triangular sublingual fold through which Wharton’s Ducts pass. The latter open on caruncule sublinguales, as in the Orang-Outan, but it was not at all clear if these were overlapped by plice in the specimen which I examined.
In the presence of the bare area on the base of the dorsal surface and in the characters of the openings of Wharton’s Ducts, the tongue of the Siamang agrees with that of the Orang- Outan, and differs from the tongues of all the other Simiide.
Genus Hy LoBATEs.
THE SLENDER GrBBon (ZZ, agilis).
I have not had the opportunity of examining the tongue of H. agilis, but Flower (28) points out that it has the following
characters :—
1. The tongue narrows slightly from base to apex.
2. The apex is obtusely rounded.
3. The vallate papille are small, irregularly placed, and adopt the V-formation.
4, Fungiform papillz are large and evenly distributed 2*
20 DR, C. F. SONNTAG ON THE ANATOMY
5. Conical papille short and thick on the anterior part of the dorsum.
6. Conical papille at the base of the tongue large, soft, and pointed. ;
7. Lateral organs distinct.
8. Sublingual fold bifid.
Tue Hoorock Gipson (f. hoolock). (Specimen No. J. 357.2, Mus. R.C.S.)
The tongue is short, compact, and rough, and tapers from base to apex (text-fig. 6).
The apex is rounded and has no mesial notch. It bears conical and fungiform papill, but the latter are small and inconspicuous. The Jateral borders are the same as in S. syndactylus, but are shorter.
The Papille.
The papille have the usual general distribution, but there is no smooth non-papillary area at the base as in S. syndactylus.
The Circunwallate Papille.
There are four vallate papille arranged in the Y-form. Two are mesial, and there is a right and a left lateral papilla (text-fig. 6).
The right and left lateral papille are level with the central lamine and sulci of the lateral organs. They are circular on plan and conical on elevation, the narrow ends being attached to the bottoms of the fosse. The fosse are plain, and the vallums are lobulated and surrounded by conical papillee.
The two mesial papille (text-figs. 6 & 9, 19) are close together. The anterior one is circular and the posterior one is oval on plan, and both are conical on elevation with the broad ends free. Both Jie within a depression surrounded by a prominent lobu- lated ridge of mucosa, and the space between them and the latter is crowded with small cylindrical conical papille. The fosse are not very prominent. All around the common rampart there are conical papillee.
The Fungiform Papille.
The fungiform papille are disposed over the whole of the anterior two-thirds of the dorsum. As many of them are con- cealed by the conical papilla, it is necessary to employ a lens to detect them all. The largest ones on the dorsum are immediately in front of the vallate papille, but all the others are small. There are few on the lateral-borders of the tongue. On the papillary zone of the iferior surface they are larger than any- where else. They occupy most of the zone beneath the apex, but farther back they are arranged in an irregular double row, on which some of the papille are hemispherical and others are
OF THE TONGUES OF THE MAMMALIA. 21
pedunculated. Some run into the lateral organs (text-fig. 6
FP).
The Conical Papille.
On the anterior two-thirds of the dorswm the conical papille are strong and coarse, and give the tonguea rough appearance. Their disposition in clusters and rows is not very clearly marked, but is maintained. Several groups are arranged in an undulating manner, and the points of the papillae point backwards, back- wards and outwards, or backwards and inwards (text-fig. 6). They conceal several of the fungiform papille.
?
Text-figure 6.
OS VO,
The tongue of Hylobates hoolock, showing the dorsum, inferior surface, and right lateral organ.
Behind the vallate papille the tongue is covered with cylindrical conical forms. On the area lying between the lateral vallate papille and the level of the posterior pole of the rampart common to the two mesial vallate papille they are small, but behind that level they are large, and many have strong single processes (text- fig. 9,5). There are some small cylindrical forms anterior to the vallate papillee.
The characters and disposition of the conical papillae on the sides and inferior surface are the same as in all other Anthropoids.
The Lateral Organs (text-fig. 6). Right organ: Length 1:2 cm. Ridges 12. Sulci 13. Left organ: Length 1:25em. Ridges 10. Suler 11.
22 DR. C. E. SONNTAG ON THE ANATOMY
Both organs are convex inwardly and lie on the lateral borders, with the inner extremities of their ridges and sulci on the dorsum. In the specimen (No. J. 357.2, Mus. R.C.S.) which I examined more of the left organ is on the dorsum, but that may be produced by mechanical distortion. Most of the ridges are sub- divided, and fungiform papille invade the anterior ones on both organs, Simple folds of the mucosa lie anterior to each organ, and the lateral vallate papillz are level with the central laminz and sulci. han
The following structures are absent :—
1. Large lymphoid nodules with cential pits. 2. Lytta.
3. Plice fimbriate.
4. Apical gland of Nuhn.
5. Foramen cecum.
The frenum is of moderate length.
The ventral mesial sulcus is narrow, deep, and lodges an antero- posterior crest. It runs back from the posterior border of the papillary zone to the triangular depression into which the frenum passes.
The bifid sublingual fold is not present in the specimen in the Museum of the Royal College of Surgeons, and the frenum passes straight from the triangular pit on the inferior surface of the tongue to the mucous membrane of the floor of the mouth.
THE Bornean Gipson (/7. muellerd).
The specimen described helow was obtained from a female Gibbon from Borneo which died in the Society’s Menagerie.
Measurements.—Total length 6°5 em. ; length from the apex to the central vallate papilla 5°25 cm.; length from the central vallate papilla to the epiglottis 1:25 cm.; width between the attachments of the anterior faucial pillars to the edges of the tongue 2°8 cm.; width of the apex 1:4 cm.; thickness at the central vallate papilla 1:2 em. ; thickness of the apex °6 cm,
The tongue is, therefore, long and narrow, and it is pig- mented.
Pigmentation.—The dorsum in front of the vallate papille is bluish black in eolour, and the glistening bluish-black fungiform papille appear prominently on it, as their colour is darker than the rest of the dorsum. The dorsum behind the vallate papillee is not pigmented, is white, and the lateral organs lie at its antero- Jateral aspects.
The inferior surface has a central unpigmented area shaped like the head of a spear, whose apex reaches the posterior border of the papillary bounding zone. From the posterior extremity of the hastate central area a narrow clear band runs on each side to the lateral organ, and thus brings the clear areas of dorsum
OF THE TONGUES OF THE MAMMALIA. 25
and inferior surfaces into continuity. The rest of the inferior surface is bluish black in colour.
A pex.—The obtuse apex has a fine central notch. It bears fine conical papille on the dorsum and lateral borders, and both conical and fungiform papille on the inferior surface. The conical papille are of the cylindrical and filiform types, and the latter have their points directed backwards. The numbers of points differ greatly.
Median sulci.—Median longitudinal sulci are present on both dorsum and inferior surfaces. The median dorsal suleus runs back from the apex for a distance of 1:4 em. The median inferior sulcus begins at a point *5 cm. posterior to the apex for 1-5 cm., becoming wider as it goes, till it opens into a triangular area to which the frenum is attached. It is shut off from the apex by the papillary border.
Lateral borders.—The lateral borders have fungiform and conical papille. The latter are both cylindrical and filiform with their points directed backwards.
The inferior surface.—The inferior surface is surrounded by a papillary border which is rough to the touch; it varies in width from *2 cm. at the apex to °5 cm. at the lateral organs, so it becomes wider when it is traced backwards. It bears beth fungi- form and conical papillae. The former are arranged in two rows, of which the inner one consists of closely-set elements, but the outer papille are more discrete. There is, however, no disposi- tion according to size, for both rows have different sizes of members. ‘The conical papille are cylindrical and filiform with their points directed backwards.
Internal to the papillary border the mucous membrane is smooth and, with the exception of the mesial sulcus, furrowless.
Plice fimbriate, lytta, foramen cecum, and the Apical gland of Nuhn are absent.
The Papille.
Papille cover the entire dorsum, the apex, lateral borders, and a bounding zone of the inferior surface.
The Circumvallate Papille.
There are three vallate papille arranged in the form of a triangle whose apex is in the mid-line posteriorly, and the vertical angle included is obtuse. The lateral papillee, which are simple, are *7 cm. distant from the compound apical papilla and 1:3 em. from one another. «
The apical papilla is very prominent, is oval in shape with the long axis antero-posterior, and measures *6 em. by “3 cm. Its fossa is narrow and irregular, and lodges two elements (text- figs. 7 & 9,17). These have smooth glistening bodies, and the anterior one has a small central depression. The entire series of elements is dumb-bell-shaped and the vallum sends small lobules
24 DR, C. F. SONNTAG ON THE ANATOMY
into its hollows. The vallum is finely lobulated. Perhaps this: papilla has been formed by fusion of elements similar to those in the mesial limb of H. hooloch (text-fig. 9, 19).
The two simple lateral papille are ovoid, and the papillary bodies and vallums are granular (text-fig. 7).
All the papillz are conical on elevation, the broad ends of the. cones projecting beyond the vallums (text-fig. 9, 17).
The Conical Papille (text-fig. 9, 1-13).
The conical papille have the usual arrangement in clusters and rows of varying degrees of obliquity, and belong to the cylindrical and filiform series. The latter have one or more points, all of which are directed backwards. Those shown in text-fig. 9, nos. 1-5, have shafts circular on section, but the papille (text- fig. 9, 6-8) are flat.
Text-figure 7.
The tongue of Hylobates muelleri.
a, central fungiform papilla; 6, d, conical papille; ¢, epiglottis; 7, papillary bounding zone of inferior surface; m, part of frenum; 2, frenal lamella; 0, p, mesial ventral sulcus: g, pigmented area ; 7, unpigmented area.
At the base of the tongue there are large conical papillae whose points are directed backwards and inwards. Their surfaces are granular, and they may have prominent secondary papille. They are not so well developed as in the Gorilla and Chimpanzee, but their secondary processes are larger than in either of these animals. ‘They are shown in text-fig. 9, 9-13. Nei
The Fungiform Papille (text-fig. 9, 14-16). There is little to note about the fungiform papilla. They have the same type of arrangement as in the other Anthropoids, and
OF THE TONGUES OF THE MAMMALIA, 25
they are evenly distributed. They are most numerous behind the apex on the dorsum and inferior surface.
The Lateral Organs.
The lateral organs, as in the Chimpanzee, lie on the sides of the tongue, with the upper ends of their fissures and ridges pro- jecting on to the dorsum (text-fig. 7). Hach organ is convex inwards, and has both plain and subdivided ridges. The two organs are compared as follows :—
Right organ: Length*9cm. Ridges 12. Sulci 13. Left organ : Length 9 cm. Ridges1l. Sulei 12.
The middle ridges and sulci of the lateral organs are level with the lateral vallate papille.
Lymphoid Tissue. Small and large lymphoid nodules are present on the base of the tongue, and some of the large ones have central pits which are, however, larger than in the Chimpanzee.
The Frenum.
The frenum is short and thick. It runs from the upper surface of the sublingual fold to be inserted into a triangular depression on the under surface of the tongue and from its under surface to the floor of the mouth.
The Sublingual Fold. The sublingual fold is triangular, and has a bifid apex and crenated edges.
THE WHITE-HANDED GrBBon (JH. lar).
T examined two preserved specimens (Nos. J.357.1 & J. 357.2) in the Museum of the Royal College of Surgeons. The former is oval in shape and the latter is conical, but the differences in form are possibly due to varying degrees of muscular contracture. They both differ also in the character of their papille and lateral organs. Unless differences are specifically stated here, the characters described are common to both.
The apex is similar to that of S. syndactylus.
The lateral borders are full and rounded. They possess both conical and fungiform papille, and the latter are very prominent ; some are hemispherical and others are pedunculated. At their posterior extremities the lateral organs are situated.
No mesial sulci are present on any part of the dorsum.
The Papille. The papille have the same distribution as in H. muellert and H. hooloek, and there is no smooth area on the base of the tongue as in S. syndactylus,
26 DR. C. F. SONNTAG ON THE ANATOMY
The Circumvallate Papille.
In specimen No. J.357.1 there are four papille arranged in the Y-formation. These are so disposed that there is a right lateral papilla, a left lateral papilla, and two mesial papille—anterior and posterior. All are small in size.
Text-figure 8.
Ht) HEA
ny
\
ie i
| NVI Ni
N
The tongue of Hylobates lar.
Two forms are shown, with dorsum (upper row) and inferior surface (middle row). The figures R and L are lateral organs of the figure on the right hand, and . -the unmarked lateral organ belongs to the left one.
The lateral papille are oval and subdivided into two by fissures, and the vallums and fosse are not very obvious.
OF THE TONGUES OF THE MAMMALIA, 27.
The mesial papille are small,the vallum of the anterior papilla consists of two ecrescentic ridges, and the vallum of the posterior papilla is large and fusiform.
The Fungiform Papille.
The fungiform papille have the usual disposition in rows and clusters. They tuberculate the apex. There are few on the lateral borders, but they are numerous and prominent on the anterior part of the papillary zone of the inferior surface. They , vary in prominence in different tongues, and the degree in which they are concealed by conical papille also varies. There is a prominent cluster immediately in front of the vallate papille, and some invade the vallate Y and are hard to distinguish from them.
The Conical Papille.
Most of the conical papille are of the filiform type, and have the usual type of arrangement on the dorsum, lateral borders, and inferior surface. Their points are directed backwards, or back- wards and inwards, and they increase in size from before backwards and without inwards. . They: conceal the anterior fissures and ridges of the lateral organs. | '
At the sides of, and posterior to, the vallate papillary Y they become large and oval or round, with the apices directed back- wards and inwards, and the round ones have each a long central spine.
The Lateral Organs. Specimen 1 (text-fig. 8, R. & L.).: | Right organ: Length °8 em. Ridges 5. Sulci 6. Left organ: Length -8 em, Ridges 4. Sulci 5. - Specimen 2 (text-fig. 8). Right organ: Length 1:2 cm. Ridges 10, Svdler 11. Left organ: Length 1:25em. Ridges 10. Suler 11.
The lateral organs differ in character in the two specimens. In specimen 1 there are six or five sulci appearing as slits running obliquely forwards and upwards, and the intervening lamine are coarse, short, and not greatly raised above the level of the surface of the tongue. In the second specimen the organs have the appearance usual in all the other Gibbons. .
The following structures are absent :—
1. Lymphoid nodules with central pits. 2. Lytta.
3. Foramen cecum.
4, Plice fimbriate.
The sublingual fold is triangular in shape with a bifid apex. From its upper surface the short Jrenum passes to the inferior
28 DR. C.F. SONNTAGOON: THE ANATOMY
surface of the tongne and Hoe ‘its: ander: surface to the floor of the mouth. > —
The ventral mesial ends Tagine, anteriorly at the posterior border of the papillary zone. It is narrow and deep, and lodges a small median crest. ee 0
Text-figure 9,
Papilla of the-Gibbons,
1-13, conical papilla; 14-16, fungiform papille ; 19, vallate papillae of H. hoolock.
SUMMARY AND. CONCLUSIONS.
1. Apical notches and mesial dorsal sulci are more frequently absent than present, and are of no particular value for compa tive purposes.
2. The lateral borders have the same characters as regards papille in allforms. In the Chimpanzee and Gibbons they lolge the greater part of the lateral organs, but in the Gorilla and Orang they only lodge a small -part.
3. The vallate papille are usually. fewer than in Man (7-12). In the Orang they are in V-formation, but they usually assume the Y-type in others. Compound papillee are common.
4, Filiform papillae are the predominating type of the conical group on the anterior two-thirds of the dorsum.
5. The long conical papillee on the base are largest in the Gorilla, smaller in the Chimpanzee, smallest in the Gibbons, and absent in the Orang. :
6. Only the Orang and Siamang have smooth non-papillary. areas on the base.
7. Plice fimbriatz are abceut fo the Gibbons.
8. Median ventral crests occur in the Gorilla and. some Gibbons.
9. The Orang and Siamang have no triangular sublingual fold, but all the other Simiz. possess one. In the Gorilla the apex is entire, but in all the rest it is bifid. |
OF THE TONGUES OF THE MAMMALIA. 29
10. Only Man and the Orang have the Apical Gland of Nuhn,
11. The tongue of the Orang resembles that of Man more closely than any other one does, and the tongue of the Bornean Gibbon resembles, in many ways, those of the Cercopitheques, which will be described in my next paper.
BIBLIOGRAPHY.
The numbers included in round brackets correspond with those in Professor Arthur Keith’s “‘ Introduction to the Study of the Anthropoid Apes” (Natural Science, vol. ix. 1896, Rep. 1897). ‘hose included in square brackets refer to the following papers not mentioned by Professor Keith :—
1. Miincou.—Morphol. Arbeiten, Bd. 6, pp. 605-690. 1896. 2. Boutart & Pinurer.—Journ. de ]’Anat. et de la Physiologie, Paris, 1885, p. 337.
[I was unable to see the characters of the part of the frenum running between the inferior surface of the frenal lamella and the floor of the mouth in the specimens in which I have not specifically described this part. |
Jipeaia tise
id a
ON A RARE PARASITIC FLY. 31
2. Note on the Capture (in London) of a rare Parasitic Fly, Hammomyia (Lylephila) unilineata Zett. By Lt.-Col. S. Moncx'ron Copeman, F.R.S., M.D., F.R.C.P., F.Z.S.
| Received October 14, 1920: Read February 8, 1921. ] (Text-figure 1.)
The exceptional rarity of this fly, of which I have had the pleasure of presenting to the British Museum (Natural History) the only specimens in our national collection, affords reason for a record of its capture in considerable numbers in London (Prim- rose Hill) during the past two years, for some discussion of its nomenclature, and for a brief account of its seasonal prevalence and habits so far as they are at present known.
In a previous communication I have set out some facts as to a flourishing colony of a burrowing bee (Andrena fulva) on a localized area on the south-western slopes of Primrose Hill, which has been kept under observation over a period of six years, during the latter half of which period the number of individual burrows has, for reasons which were explained in my previous paper, increased to a considerable extent. It was while watching the operations of the bees on an outlying portion of this colony, on May 16,1919, that, for the first time, I observed and obtained specimens (two in number) of a fly which, from its actions, which I studied carefully for some time, is apparently a parasite of the burrowing bee.
On the morning (about 10 a.m.) of this day, which was bright, without obvious breeze, I was lying motionless on the grass watching the bees leaving and returning toa collection of burrows on a small patch of bare earth, when my attention was attracted by a homeward-bound bee, which, on approaching its burrow, dived stright down into it, instead of, as usual, hovering around for several seconds before doing so. As it approached, I noticed that it was followed by a couple of flies, of a species unknown to me, which appeared for the moment to be as astonished as I was at its precipitate retreat into its burrow. After what looked like a fight with one another for a few moments over the surface of the ground, one of them followed the bee down into the hole, re- appearing almost immediately, and then again descending into the burrow, this time backwards. Meanwhile, the second fly remained on guard outside. When the first fly at length emerged head foremost, both of the flies were eventually trapped in a match-box, a net not being available at the time. But unfor- tunately one of them managed to escape before they could be taken home and killed. The remaining specimen was despatched at once to Major E. E. Austen, D.S.O., at the British Museum (Natural History), with a request for its identification, as the species was unknown to me. Under the circumstances, it may
32 LT.-COL. 8. MONCKTON COPEMAN ON
be of interest to quote from Major Austen’s reply, of May 17th, 1919, as follows :—
“The fly enclosed with your letter is a most interesting thing, and I am more than sorry that I have been unable to name it FOr YOU 0. 0% The species of the genus Wiltogramma (fam. 'Tachi- nide) and its nearest allies behave exactly as you described, and on more than one occasion I have watched one of these flies stalking
Text-figure 1.
Hammomyia (Hylephila) unilineata Zett., 2.
(The mark in the centre of the thorax is due to the fly having been pinned before the photograph was taken.)
Magnified x10.
a solitary bee as a stoat does a rabbit—moving when the bee moved, stopping when the bee stopped, and so on. Judge of my surprise, therefore, when, on opening the box, I found an insect such as, to the best of my belief, in nearly thirty years’ experience of Diptera, I have never seen before! ‘The species undoubtedly belongs to the Anthomyide—not to the Tachinide,—but is aber- rant in more than one respect. It is not represented either in our own collection or in the series presented by the late
A RARE PARASITIC FLY. 33
Mr. Verrall (the result of some fifty years’ collecting). My col- league, who works at Diptera, dees not know it, and [ have spent some hours.... trying to work it out with books ete., but without success. Itis a most surprising thing, especially in view of the locality. I hope that you will be able to secure more specimens, and of both sexes.”
Mr. Austen, at first, was of the opinion that the sex, not only of this particular fly, but also of each of a number of similar specimens that I was subsequently able to send him, was male, but when, later on, at the suggestion of Mr. Collin, who had learnt of my find through Professor Poulton (to whorh I had given some specimens for the Hope Collection at Oxford), one of the flies was dissected, leading to the discovery of a perfect ege, it became obvious that the flies that had been captured must be females. And itis a curious and interesting fact that among about fifty specimens of this fly which have been caught (all in the same locality) up to the end of their seasonal prevalence in the early part of June of the present year (1920) not a single individual of the male sex has been secured. I learned, however, from Mr. Collin that he now possesses three specimens of the male in- sect—two taken by the Rev. A. H. Haton at Seaton (Devon) and the third taken by himself at Long Sutton in Hampshire, all in May 1919, curiously enough the same year and month in which the first specimens (females) were found by myself on Primrose Hill. My. Collin further informed me that he possesses female specimens from the following localities :—‘* Newmarket, Shoebury- ness, and Dunsford (all June captures); Cuckmere (Sussex) taken in May; and a spetimen taken by Col. Yerbury at Charlton in April.
The difficulty as to the sex of my first captures arose from the masculine character of the approximation of the eyes, which is the cause of the very narrow “ frons,” which, however, appears to be peculiar to, and distinctive of, the female in this group of An- thomyids—a feature which is well shown in the photograph, and which, so far as | am aware, has not previously been illustrated.
NoMENCLATURE.—As stated above, Major Austen and _ his col- league in the Diptera department of the British Museum (Natural History) were unable, at first, to identify this fly, but on calling there on May 28th, 1919, with somefurther captures, Major Austen informed me that Dr. P. H. Grimshaw of the Royal Scottish Museum, who had recently paid him a visit, had stated, when the specimens were shown to him, that he recognised the fly, iden- tifying it as Chortophila buccata Kallén, although the species was not (as Major Austen understood him) included in the Scottish collection.
Shortly afterwards Professor Poulton arranged with Major Austen that Mr. Collin should be afforded opportunity of examining the specimens I had presented to the Museum, for the reason that, as Mr. Collin informed me, his uncle, the late Mr. Verrall, had suggested that a fly, apparently identical
Proc. Zoou. Soc.—1920, No. III, 3
34 ON A RARE PARASITIC FLY.
with mine, should be known as Hammomyia unilineata Zett. rather than WZ. (Chortophila) buccata Fallén.
Subsequently Mr. Collin wrote to me that he possessed several continental specimens of H. buccata Fln., including a pair so named by Zetterstedt himself, and that he was of opinion that these were abundantly distinct from the British species, which is undoubtedly Hammomyia (Hylephila) unilineata Zett. Further- more, he kindly directed attention to the fact that in describing unilineata Zetterstedt wrote ‘ Feminee ad nidis Andraenarum invente, in quarum larvis larvee hujus speciei Ariciz verisimiliter parasite vivant observante D. Professore Wahlberg.” Appa- rently, therefore, buccata Fallén requires confirmation so far as our British fauna is concerned, as Mr. Collin is convinced that he has never seen a British specimen of the true buccata.
SEASONAL PrEVALENCE.—AS stated above, my first specimens of this fly were captured on Primrose Hill on 15th May, 1919. On the same cireumscribed area of ground I caught ten more speci- mens on May 19th, ten on May 20th, and seven on May 21st. Then, after an absence from town of several days, a further seven flies were caught on May 27th and three on May 29th—at which date I had again to leave home for about a fortnight. Just before my return the fine weather gave place to rain, accompanied by a considerable fall in temperature, with the result that, subsequently, neither bees nor flies were to be found, notwithstanding careful search on several successive days.
It may be mentioned that, in 1919, Andrena bees were first seen on May 6th, a warm and sunny day, when a number of males, which always emerge before the females, were flying about; while females were not found, with the exception of one or two solitary specimens, until several days later. So that, as might be expected in view of what is known as to the parasitism of the fly in question, it is obvious that the seasonal prevalence of the female of both fly and bee tallies closely.
In consequence, doubtless, of the abnormal meteorological con- ditions during the present year (1920), both bees and flies appeared at an earlier date than in 1919, the first flies, three in number, having been obtained on May Ilth. Careful search was made for male specimens of the fly, but again without success. By the end of May both bees and flies had disappeared.
It will be noted that, with some exceptions, the specimens of the fly in Mr. Collin’s collection were captured in the month of May—the month during the latter half of which, as my obser- vations on Primrose Hill, extending over a period of several years, have shown, the female of the bee Andrena fulva 1s more particularly prevalent.
ON THE CLASSIFICATION OF THE ‘THERIODONTIA, =)
Or
3. The Bases of Classification of the Theriodontia.
By D. M. 8. Watson, F.Z.S., University College, London. [Received October 19, 1920: Read February 8, 1921.] (Text-figures 1-29.)
Among the first series of reptiles from the Karroo system of South Africa sent home by Andrew Geddes Bain were a few poor fragments of animals with a heterodont carnivorous denti- tion. Later collections from the same rocks included more satisfactory remains of these animals, which were described by Owen, who recognised their mammalian appearance and despite his ante- evolutionsur y views even suggested that they were mam- malian ancestors. Prof. Seeley’s visit to South Africa marked a turning-point in our knowledge of these reptiles, because he showed that their remains were found in rocks of widely different ages, and that the latest assemblage—Diademodon, Cynognathus, and 7irachodon—were more mammal-like in their dentition than were their earlier forerunners. He showed also that they pos- sessed a mammal-like secondary palate, but failed to arrive at a satisfactory interpretation of that region in the less complete remains of the earlier forms known to him. Neither Owen, Seeley, nor Lydekker was able to draw up any useful classification of these reptiles on account of the paucity of material, and the first definite step in so doing was made by Broom, when in 1904 he showed that Scylacosaurus sclateri, a form from the lowest zone of the Beaufort beds, differed from the ‘‘Cynodonts” of the highest zone of that formation in lacking any trace of a secondary palate.
Subsequent work by Broom added many new generic types to those included with Scylacosawrus in that primitive division of the carnivorous Therapsids whose members lacked a secondary palate and had uncusped molar teeth. This division Broom made into an order and called Therocephalia.
No further important additions were made to our knowledge of the skull of any of these reptiles till, in 1911, the writer gave a very detailed account of the skull of Diademodon and Broom a more general description of the skull in all the Cynodonts. The first important addition to our knowledge of the earlier Theriodonts was the description by the present author of the posterior half of a skull from the Cistecephalus-zone, which agreed with Gorgonops in having a broad parietal region, the parietal bone being excluded from the margin of the temporal fossa. In the same paper some of the more salient features of the palate of Gorgonops were described, and it was indicated that the form showed the beginnings of the Cynodont secondary palate, the skull known as Arctognathus curvimola showing an intermediate condition. Whilst I was writing this paper in
3%
36 MR. D. M. S. WATSON ON THE
London, Broom in Seuth Africa was describing two very com- plete Gorgonopsid skulls, one associated with the anterior part of a skeleton. Of these skulls Broom gave a good description, bringing out the whole structure of the face and parietal region, but not giving us so satisfactory an account of the palate and occiput. Broom, sometimes in conjunction with Haughton, sub- sequently added many new and often strange forms to the Gor- gonopsidee—on the whole, emphasizing rather their resemblance to the Deinocephalia and Dicynodontia and even Pelycosauria than those which they show to the “Cynodontia.” In 1914 I was able to show that known Gorgonopsids could be arranged as a morphological series giving a gradual passage in the structures of the occiput, and of the basicranial and otic regions between Dimetrodon a Pelycosaur and Diademodon a “*Cynodont.” In the same paper I described the palate of the ‘ Cynodont” Bauria, showing that it differed much from the Cynognathids and resembled the non-Gorgonopsid Theriodonts with a primi- tive palate more than the Gorgonopsids. In consequence, purely as a temporary measure, | revived the order Theriodontia and divided it into four sub-orders—the Therocephalia, the Gor- gonopsia, the Bauride, and the Cynodontia. Since that paper was written, Haughton has published descriptions of certain new forms and made important new additions to our knowledge of the brain-case of the earlier Theriodonts. In his most recent paper he uses provisionally my 1914 classification, emphasizing its insufficiency.
In revising a paper on the relative ages of the Paleozoic and Triassic reptile- bearing rocks, which has occupied me at intervals for some years, 1 was forced to deal with the problems presented by the fauna of the copper-bearing Permian sandstones of the Orenburg district of the Urals. One of the most noteworthy forms from this locality is Rhopalodon, an animal whose skull, which alone is certainly known, presents many resemblances to the Gorgonopsids. The necessity of discussing the systematic position of this form led me to an examination of all the Theriodont material available, with the results which are set out below.
It is convenient to begin with a description of the material at my disposal, then to discuss the morphological results which arise from it, and, finally, consider the evolution of the group and the relationship of Deuterosaurus to it.
ARCTOPS WILLISYONI Watson, Proc. Zool. Soc. 1914, p. 1026.
Type and only known material: a skull lacking the anterior part of the snout, the quadrates and quadrate rami of the pterygoids, otherwise complete and practically undistorted. From Howse Post, near Fort Beaufort, 8. Africa, not improbably E,NDOTHIODON zone.
I deseribed and figured the oceiput and basicranial region in the oviginal description.
CLASSIFICATION OF THE THERIODONTIA. 37
Arctops has a depressed and very massive skull, the snout, when broken off about 5 em. in advance of the orbit, being rectilinear in section, bounded by a straight dorsal surface which passes somewhat abruptly into straight, nearly vertical, lateral surfaces. The orbit is small, placed high in the skull, and nearly laterally directed; its upper margin is continued forward by a ridge separating the dorsal surface from the lachrymal region, which is excavated into a shallow depression. ‘I'he interorbital region is very wide, forming a flat surface bounded laterally by shallow bays over the orbits.
Text-figure 1.
5a. Tae, |Par. BOc. ExOc. Au.Ga.
Arctops willistoni Watson. ‘Type-skull. Dorsal aspect. 2. B.Oc., basioccipital; I.Par., interparietal ; Sq., squamosal ; Tas., tabular.
The parietal region, also flat, is even wider than the interorbital surface ; ib separates the very small temporal fossxe which face more largely laterally than dorsally. The occipital surface is very wide and is separated from the parietal by a sharp corner. The squamosal is small, consisting mainly of a vertically standing plate passing directly outward from the end of the massive paroccipital process. The posterior surface of the bone at this articulation is produced backwards into a ridge which forms the
38 MR. D. M. S. WATSON ON THE
inner wall of the auditory groove. Sutures over the outer surface are not clearly recognisable.
I have already described the basieranial region, but would again call attention to the flat, laterally directed, plate-like basi- pterygoid processes. The narrow ridged girder formed by the parasphenoid and pterygoids extends forward to the front of the orbit, where it suddenly passes into the wide posterior end of the palate. The pterygoids pass outward to form thick downwardly directed flanges, not very deep when compared with later forms, but of great antero-posterior extent. The middle region of the posterior part of the palate forms a slightly raised area separating two concavities, whose surface lies mainly on the ectopterygoids, large square bones which only take a small part in the great flanges. The middle part of the palate forms a shallow groove
Text-figure 2.
Arctops willistoni Watson. Type-skull. Right lateral aspect. x2.
B.Sp., basisphenoid; Pr., pterygoid.
beginning at the extreme posterior end and running forwards to the posterior nares. At about the level of the anterior end of the ectopterygoid, this groove is overhung by a pair of small processes rising from the ptervgoids. Further forward the floor of this groove is cut into by the narrow slits which represent the posterior ends of the posterior nares, These are separated by a narrow bar of considerable vertical depth. The structure of this bar is not quite certainly determinable, but on the curved fracture which forms its present front termination it is certain that its upper surface consists of a pair of ridges separated by a parallel-sided cleft not more than a millimetre wide and nearly a centimetre deep. From this slit a suture seems to be continued on to the palate. Further back two lateral ridges are
CLASSIFICATION OF THE THERIODONTYA, 39
added to the original pair, the gaps between them being also apparently continued as sutures on to the palate. ‘Thus the posterior part of the bar separating the internal nares seems to be built up of two pairs of bones, of which the outer terminates not far in front of the posterior ends of the nares. It is probable that the inner pair are prevomers and the outer the anterior ends of the pterygoids, which hence form a part of the border of the posterior nares.
Text-figure 3.
Arctops willistoni Watson. 'Type-skull. Palatal aspect. X $. Ee.Pr., ectopterygoid; Par.Oc., paroccipital ; Pr., anterior end of pterygoid; P.V. ?, prevomer, posterior end of internarial bar. Parts in broken lines restored without evidence.
GorGoNnops ToRVUS Owen, Cat. 8. Afr. Rept. 1876.
Type: a skull with the zygomatic arches broken away, the basis cranii only represented by a fractured surface passing horizontally through the basisphenoid. The paroccipital pro- cesses only represented by the impression on the matrix of the anterior face of that of the right side, the posterior part of the palate represented only by the impression of its dorsal surface.
40 MR. D. M. 8. WATSON ON THE
Otherwise the skull is complete and, on the whole, extremely well preserved. It is represented by beautiful and most accurate lithographic drawings in Owen’s Catalogue. From Mildenhals, Fort Beaufort. Another more complete, but less well-preserved, skull from the Hndothiodon-zone of Beaufort West is in the American Museum of Natural History.
Text-figure 4.
Ban Peis lee rae neds
Gorgonops torvus Owen. ‘Type-skull. Dorsal aspect. Xz. Parts in broken line restored without evidence.
Fr., frontal; I.Par., interparietal; Pr.FR., prefrontal; P.O., postorbital ; Pr.FR., postfrontal; S.Mx., septomanxilla; S.Oc., supraoccipital.
The skull of Gorgonops has a flat dorsal surface, which passes through a chamfered corner into the nearly vertical sides of the snout. The orbit is large, directed almost entirely laterally and of considerable depth. Immediately in front of it the snout is
CLASSIFICATION OF THE THERIODONTIA. 4]
nearly square in section, the lachrymal region being excavated into shallow hollows prenhane by a thickening of ine prefrontal, which forms the lateral border of the flat dorsal surface. Fur ther forward the snout becomes deeper, the nearly flat lateral surface passing by a rounded corner into the dorsal surface. There is a long broad swelling on the maxilla over the root of the canine.
The interorbital and parietal regions are both very broad, the latter passing smoothly into the broad occipital surface. The part of the occiput preserved consists mainly of the very broad interparietal, whose sutures with the tabulars are shown. ‘The supraoceipital has only a very shallow exposure below the inter- parietal. A peculiar feature of this skull is the irregular shape of the pineal foramen and the fact that that opening is raised on a little column standing up above the general level of the parietal region.
Text-figure 5.
al) Fe Fr. Na. SMx.
x SSS
pore —— —
~
if it Kj / | ]
pe ah oe oy
er Wrens ali: ; PMx.
Gorgonops torvus Owen. Type-specimen. Right lateral aspect. 3%. Parts in broken lines restored without evidence.
Ju., jugal; Lac., lachrymal; Mx., manxilla; P.Mx., premavxilla.
The general structure of the dorsal and lateral surfaces will be best understood from text-figs. 4&5, The cruciform shape of the pair of frontals is noticeable.
The structure of the external nostril is very well shown in the specimen. The dentigerous part of the premaxilla is deep, and articulates directly with the anterior end of the maxilla, which overlaps on to it. The dorsal surface of the two bones is the lower margin of the nostril and forms the emplacement of the septomaxilla. Behind the nostril the maxilla rises to a long suture with the facial part of the septomaxilla; behind this bone it reaches the nasal. The nasals forma slightly coved roof to the olfactory chamber and reach forward almost to the end of the nose, where they terminate in a nearly straight margin, from the middle of which arises the narrow process which articulates with
42, MR. D. M. S. WATSON ON THE
the facial processes of the premaxilla. The facial part of the septo- maxilla articulates with the lower margin of the nasal, but the two bones separate before the nasal terminates, so as to leave that bone overhanging the nostril like the eaves of a roof. After its separation from the nasal the septomaxilla passes downwards and gives off a process from its anterior border, which passes inwards towards the middle line, following the curve of the
Text-figure 6.
Gorgonops torvus Owen. ‘Type-specimen. Palatal aspect. 32. Unshaded areas surrounded by continuous lines present but mutilated, broken lines parts restored without evidence.
P.V.?, internarial bar, ? prevomers ; Pat., palatine; Vo., ‘ vomer.”
anterior border of the nasal. The lower part of the septo- maxilla is a rounded column, swelling out to a base which rests on the premaxilla.
T have already (1912) given an account of the general features of the palate of Gorgonops, but, as further study of the specimen in the light of other material has enabled me to make out some
CLASSIFICATION OF THE THERIODONTIA 43
interesting features not previously recorded, I give here a more detailed description. The premaxilla has a narrow dentigerous surface, with five sockets for the roots of the incisors; above the border the bone thickens, forming a deep wall, from whose ad- median half the palatine process arises; this is at first a flat expansion, but soon becomes a rounded, backwardly directed tubercle, separated from its fellow and resting in a groove on the lower surface of the “‘ prevomer.” The internarial bar is a narrow rod which anteriorly is comparatively wide. Anteriorly its palatal surface bears a median ridge which separates two channels bounded by other lower ridges, which form the lateral borders of the bone. Further back the lower surface of the bar becomes flat, and the whole of the posterier part is only represented by a broken surface, which probably originally supported a deep median ridge.
The internal nares are very large openings bounded by the premaxilla in front, where they are very wide, and contracted posteriorly by the thickening of the maxille necessitated by the large sockets for the canines. The maxille form their outer borders for some distance and are then excluded by the palatines. Finally, the posterior border is formed by the semi- circular margin of a bone whose nature has to be discussed. Between the internal nares and the pterygo-parasphenoidal bar the palate forms a large area of complicated shape. The height above the lower margin of the premaxilla at which the palatal processes start, and the deep step in the lower border of the maxilla just in front of the canine make the ventral surface of the internarial bar lie much dorsal to the lower edges of the maxille in the cheek-region. Thus at the back of the nares the palate is very much vaulted. Behind the canine the palatal exposure of the maxilla, which bears no trace of cheek-teeth, is very broad and its admesial surface forms a deep vertical plate. This surface when followed caudally passes into a similar face carried by the palatine, which stands almost vertically, tightly attached to the maxilla by an obvious and deeply interdigitated suture, and with its lower edge forming with that bone a broad flat face in the area where cheek-teeth would naturally be expected. These teeth must have been functionally replaced by a hard gum, possibly cornified so as to form a crushing plate.
The wide groove formed by the palate at the posterior end of the internal neres is rapidly divided into three, each groove of the lateral pair is deep and narrow and cylindrical; it shallows rapidly when traced backwards, finally becoming flat when it reaches the ectopterygoid. The bottom of the lateral groove has a suture running the whole of its length, which is completely exposed on the right side, but concealed by matrix except for its anterior end on the left side of the type-skull. This suture, which seems to be truly a suture and nota crack, unites the pala- tine with the pterygoid, which bone hence forms the posterior margin of the posterior nares,
44. MR. D. M. 8. WATSON ON THE
The middle groove of this part of the palate becomes narrower as it is traced backward, but remains deep. Its hinder end is separated from the lateral grooves by triangular raised areas, which are roughened, but seem not to bear teeth.
The internarial bar is continued back into this part of the palate as a narrow slip separated from the pterygoids by a pair of open and very obvious sutures. These sutures rapidly approach and fuse, being continued backwards by an obvious median suture for about 5mm. This open suture, with a visible strip of matrix in it, then suddenly ends and is with certainty not continued backward in the middle line. It is, however, apparently replaced by a pair of much less obvious sutures, between an overlapping median bone and the pterygoids, which pass outward to the margins of the median groove and seem then to be continued backward by still less obvious sutures running along these borders. Further back the wide, essentially flat palate gives origin to the descending flanges. The ectopterygoids are separated by obvious sutures and ave comparatively small bones not taking any large part in the flange.
The palate of Gorgonops thus seems to show large pterygoids reaching forward to the posterior nares and widely separating the palatines, which are small bones simply continuing the ectoptery- goids forward. In that part of the palate which lies in front of the transverse flanges the pterygoids do meet each other for a very small distance in the middle of their length, but posteriorly are separated by a median vomer and anter iorly by the posterior end of the internarial bar which is clasped between their distal ends. There is no evidence to show whether or not these two median bones are really separated, but as the anterior passes dorsal to the pterygoids, whilst the other overlaps their ventral surface, there is great probability that they do not represent parts of the same element?
SCYMNOGNATHUS WHAITSI Broom, Proc. Zool. Soc. 1912, p. 861.
Type: a figured skull, nearly complete, but considerably erushed and showing little of the structure. Other imperfect skulls and other bones.
The individual of which, under the name of Scymnognathus whaitsi, 1 described the lower jaw (1912) and the brain-case and occiput (1914), does not belong to this species, and is deseribed in this paper as a new genus and species. There are in the British Museum three specimens of JS. whaitst:—R. 4053 collected by the Rev. J. H. Whaits, as a very large number of small fragments which, fitted together, form a skull from the front of the orbits backwards with the pro-atlas and atlas in position, the anterior end of the snout and a mass of separate fragments representing the major part of the face; of these a small bit of the posterior part of the palate is of great morphological interest. The back of the skull built up from these remains is quite un-
distorted and has been very completely developed, now showing
CLASSIFICATION OF THE THERIODONTIA. 45
the whole lateral surface of the brain-case, the structure of the zygomatic arches and roof of the skull and occiput with great perfection. It is in many ways the best Gorgonopsid skull known.
R, 4052. A skull retaining a well-preserved and only slightly sheared snout, with a much crushed posterior part, permittin; the definite identification of R. 4053.
49369. A snout, somewhat distorted and not very well pre- served which has been cut into slabs. It agrees well with the corresponding part of R. 4052.
All the material of Seymnognathus whaitsi comes from the Endothiodon-zone of Beaufort West. The skull, as a whole, is remarkable for the marked distinction between the relatively narrow snout and palate and the wide postorbital region. Owing to this shape, the orbits look as much forward as outward. The temporal fossee are very large and face more upwards than out- wards. ‘The parietal region is, in consequence, narrow and the occiput deeply cupped, owing to the backward swing of the squamosals from their union with the postorbitals.
The snout is much more rounded than in Gorgonops or Arctops, although towards the orbits it is still somewhat “ square-cut.” The external nares closely resemble those of Gorgonops, and there is the same step between the lower edges of the premaxilla and maxulla.
The structure of the dorsal and lateral surfaces of the skull are obvious from text-figs. 7 & 8, but it is necessary to give some account of the brain-case and palate.
The basioccipital is fused with the exoccipital and paroccipital, and its suture with the basisphenoid has been destroyed by a fracture. It isa long narrow bone, terminating behind in a single condyle, which is probably partly exoccipital. This condvle, as seen in section, 1s much wider than it is high, the dorsal sur- face being excavated by the lower part of the foramen magnum. The posterior part of the basioccipital is thus thin.
The exoccipitals are of the ordinary Gorgonopsid or Pelycosaur pattern, but thei upper surfaces are concealed by the overlapping elements of the proatlas. Further forward the lower surface of the basioccipital and of the paroccipital fused with it project down as a short, powerful, obscurely bilobed process, whose outer part supports the fenestra ovalis; with this process the powerful tuber basisphenoidalis articulates dorsally, though ventrally the two projections are separated by a gap.
The paroccipital and pro-otic are fused, not only with each other, but also with the basioccipital; the suture between the pro-otic and the basisphenoid remains open.
The paroccipital process is extremely massive, passing out from the side of the basioccipital on the lower surface of the skull to its broad abutment on the squamosal. ‘he anterior and lower faces of this process are excavated by a groove which leads inward to the large irregular opening, which is the fenestra ovalis. The
Or co)
46 MR. D. M. S. WATSON ON THE
Text-figure 7.
Scymnognathus whaitsi Broom. Back from R. 4053. Snout from R. 4052. B.M.N.H. Dorsal aspect. x4.
At., atlantal neural arch; Ju., Jugal; P.Par., preparietal ; Pr.At., pro-atlas.
CLASSIFICATION OF THE THERIODONTIA. A7
paroccipital process is bounded above by the small oval post- temporal fossa, which lies at the level of the floor of the foramen magnum.
D2,
~ sean el ny
—<$<—<——=
|
~ (IS ~ = \ ~ se
(=) =H S| ‘S) da} w~ iS) S) i M oD Ye) SS BS =) ‘i PS =e ~~ hi! F SSS (Ss : i RS SeS = jam aos i x = = | S on S =) §] Te! —_= 4 Sms iS f 1 SS oe || Sa dep at . ES ies) Bm (Us S) S wm & oO 5 oH ° = BI ac Soest ne ce » aS = S| S S an az BB ls iam fab a) y=) : on ies? al ° — wn sos Cea eres ®D id | oH OR eG vases = of Bet G Seca Bm A iS = f fea) \ q > ~~ e Sk Lb ° ae | : IS ® =E Q“\ISI S =~ —~ => = = = PS i= ~ Sy Ss Ss = = mM
In the pro-otic on its front face, above, and in front of the fenestra lies the outer opening of the foramen for the facial nerve. This opens downwards and has below it a little hollow for the geniculate ganglion. iis
Immediately above and a little in front of the facial is another much larger foramen opening directly forward ; its outer margin
48 MR. D. M. S. WATSON ON THE
is carried by a spout-like projection from the pro-otic, its inner border 1s basisphenoid. That bone immediately in advance of the foramen has a deep depressed groove. There can be no doubt that this foramen is for the fifth nerve, the cavity before it having housed the Gasserian ganglion. Above and in front of this foramen the pro-otic is continued forward, having a suture with the basisphenoid, until its anterior margin or that of the in- distinguishably fused supraoccipital is cut into by a notch, which is very nearly converted into a foramen by the basisphenoid. This foramen must be venous; it is in part the homologue of one which is almost constantly represented in Therapsids.
The supraoccipital is as always spread out into a wide plate, but from the anterior part of this expansion a special thickening
Text- figure 9.
Far. | Par Tap.
Oil. Rarer Bee
Scymnognathus whaitsi Broom. KR, 4053. B.M.N.H. Occipital aspect of skull, with the anterior ends of the proatlas attached. x 5.
Par., parietal ; Qu., quadrate; T.B.Sp., tuber basi-sphenoidalis.
is carried forward, forming the roof and part of the side-wall of the brain-case. It is this thickening whose margin forms the dorsal border of the venous notch. With the sides of the upper part of the supraoccipital in the region of this thickening the interparietal articulates, stretching far forward in contact with the parietal above and the supraoecipital below, and widely exposed in the outside view of the brain-case.
The basisphenoid is a remarkable bone, which in the speci- men is broken off in front. As far as it is preserved, how- ever, it consists of « body which is articulated with the front of the basioccipital largely through the intermediary of the two
49
SIFICATION OF THE THERIODONTIA.
~ r
CLA
inassive downward projections, which are its tubera.
*SOALOM ASO] JO JIxa ou} JOF BUTURLOF.“ YY “TTA “A f ployuopo S*aQ f Baqued1ezur pug pue JST “OYT SSqBao wBaqsatley “AQ Na ¢ prlouayds “OL GIO =, -plowyya ,, “Haig ‘ plosAroydide “Agra fsixy “xy f your [Binou [eyuepye © Ny LY—? WLM “etojoq sv s.10q4a] eoua.1OJaxT “UO1qIsOd UI SIX PUB SETIV ay] YALM “vssoF [v.1odun9}-ysod aya Jo Terpout ysnl qno pvgzqroesvaed v Aq paaowtad SI [[NYS o[} JO opts Jjo] oy} UspAr usas sv asvo-tIeBIq aq JO Joodse [B1eqVI JJorT
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articulation the bone becomes narrower where it is attached to the
Its lateral face here bears the groove for the Gasserian
ganglion, above which the bone again widens to the continuation
pro-otie.
Proc, Zoou. Soc.—1921, No, IV.
50 MR. D. M. 8S. WATSON ON THE
of its suture with the pro-otic. Above and in front of the termination of this suture the basisphenoid is still continued upward as a slender process, whose upper margin is the lower border of the great venous notch and whose lower margin meets its fellow in an open median suture below the brain, immediately in advance of the hypophysis. The rostral part of the basi- sphenoid is a vertically placed plate arising from the body of the bone and separated from the upper parts, just described, by a deep narrow notch, the open side of the pituitary fossa, From its sides arises the thick flat expansions, which are the basi- pterygoid processes. These incline downwards at the back at an. angle of about 45°, and whilst their dorsal surface is sharply separated from the vertical face of the medial lamina, which lies above them, their ventral faces pass smoothly down to form a blunt ridge on the lower surface of this part of the basisphenoid.
The parietal is composed of a plate of bone lying on the roof of the skull with an almost plane dorsal surface. Its postere-lateral corner is drawn out into a long process, which passes backwards to touch the extreme tip of the squamosal. The posterior edge of the whole bone is in contact with the interparietal towards the middle line and with the tabular laterally. By far the greater part of the outer margin of the parietal is in contact with the postorbital, which completely excludes it from participation in the margin of the temporal fossa. From the lower surface of the parietal a powerful ridge is developed, which marks the side-wall of the brain-case. Posteriorly this ridge just touches the anterior end of the supraoccipital. Immediately in front of this bone it has a suture with the epipterygoid ; further forward its lower edge is free, but gradually declines, until at or about the front end of the parietal it vanishes. The lower surfaces of the pre- parietal and frontals form the roof of the brain-case in this region, and the lower surface of the anterior part of the brain is supported by an ethmoid ossification. This is a thin hem1- cylindrical shell of bone with a rib along its ventral surface in the middle, which indicates that it rested on a deep median septum now broken away and lost.
The posterior end of the ethmoidal cavity is widely open. The opening of the anterior end is much contracted and les clese up to the skull-roof.
The floor of the cavity close to its anterior end is perforated by a pair of large oval foramina, which face downward. These are separated only by a narrow septum and must be for the optic nerves, which hence had a remarkably long intracranial course.
The epipterygoid is only represented by its upper end, which, though narrow antero-posteriorly, is thin. It has a suture with the parietal and with the front end of the supraoccipital, the latter connection being of considerable morphogenetic importance.
There is a medium-sized foramen for the Xth nerve, opening downwards and backwards below the exoccipital well above the
CLASSIFICATION OF THE THERIODONTIA, 51
Text-figure 11.
iy
U
I
ll SS
alll
5 Y
%,
: Face
Scymnognathus whaitsi Broom.
Posterior part from R. 4053. Snout reconstructed from a series of transverse sections of 49369 completed from R. 4052. Ectopterygoid region + detached area including the vomer R. 4053. #4. B.Pr., basipterygoid process.
4%
52. MR. D. M. S. WATSON ON THE
bottom of the skull. There isa single hypoglossal foramen in the usual position.
Taken as a whole, it is obvious that the brain-cavity was very small in relation to the skull, and especially that the cerebral hemispheres were still of much less bulk than the cerebellum. At the same time the very great proportional length of that part of the brain which lies in front of the fifth nerve foreshadows the great cerebral development which occurred in later allied forms.
The palate of Seymnognathus whaitsi is still not known as a whole, but the anterior part is very well shown in the sections of 49369, from a reconstruction made from which text-fig. 10 is mainly drawn, and in the solidin R, 4052. The pterygoidal flange and one transverse bone are preserved in position in R. 40538, and that individual retains a small fragment from the middle of the palate just in front of the anterior end of the long pterygo- parasphenoid bar. This fragment shows a pair of much raised ridges, which lie on the pterygoids and diverge outwards as they are traced forward. These are covered with a shagreen of small teeth. Between these the palate is deeply grooved ; lateral to them it is depressed into deep hollows. The dorsal surface of the fragment bears a deep median keel. This fragment has been cut across by a tranverse cut, so that it now shows three sections. That at the back shows that the keel is formed by a single bone whose lower edge is received into a groove on the upper surface of the fused pterygoids, which meet below it. In the middle section this median bone has a deeply grooved lower edge, the two thin ridges which form the side-walls of this groove being received in slits in the pterygoids. These latter bones meet in a median suture on the palate and here bear the massive tooth-bearing ridges. On the front section the median bone is exposed on the palate, forming the roof of the median groove and separating the pterygoids. ‘The median bone thus corresponds exactly in position and relations with the posterior median bone in Gorgonops and the back of the vomer in Diade- modon. The anterior part of the palate resembles that of Gor- gonops in the relation of the internarial bar to the palatine process of the premaxillse and in its shape.
Near its anterior end the internarial bar is a single bone with a convex dorsal surface from which a ridge rises. This ridge, which is detached, apparently by fracture, extends upwards and backwards, obviously representing an ossification in the nasal septum. The lower surface has a low median ridge separating two well-defined grooves. As this bone is traced backward it gradually becomes narrower from side to side until in the region of the first molar tooth, where it is seen in section (text-fig. 12). it has become converted into a plate 35 mm. in depth and only two millimetres thick at the lower edge, where it is widest. The dorsal centimetre of this narrow septum is clasped between two
CLASSIFICATION OF THE THERIODONTTIA. 53
thin films of bone, whose outer surfaces ave in contact with another pair of similar slender processes. Hven in this region the lower edge of the median bone still les considerably dorsal of the tooth-bearing margin of the maxilla.
In the next section, about 1 cm. further back, the median plate is shallower, its dorsal margin being curved downwards. The two pairs of plates which support its upper edge are thicker, but still retain their same relations.
The next slab has fortunately been split longitudinally and somewhat developed, so that it gives conclusive evidence that the lateral pair of processes described above are part of the
Yext-figure 12.
Scymnognathus whaitsi Broom.
Series of transverse sections at about 1 cm. interval, across the snout of No. 49369. B.M.N.H. 1, anterior section; I.N.B., internarial bar; in 2-5 only the internarial bar is represented; in 6 the maxillz and palatines are shown ; in 7 only the anterior ends of the palatines and pterygoids. 5.
palatines. The inner pair pass down to the ventral surface and there form a little boss on the palate, which separates the two deep grooves on the palatines. These grooves are so overhung by the more ventral parts of the palatines that their floor can scarcely be seen in a direct ventral projection No sutures can
54 MR. D. M. S. WATSON ON THE
be seen in the little median boss, and it is probable that the median element of the internarial bar has terminated in it.
The vertically standing part of the palate, which forms the side-wall of the groove just described, descends to the level of the lower border of the maxilla, where it passes into a flat, thick, horizontally lying plate, which extends outward to the lower edge of the maxilla with which it has a suture.
This horizontal part of the palatine forms the greater part of that bone, and extends backward and forward in contact with the maxilla, until by narrowing and increasing in depth it becomes converted into a mainly vertically disposed plate, which forms part of the side-wall of the posterior part of the very large internal nares. It then terminates.
Text-figure 13.
HOUERUE Ve aie Wy WLU DSRS tae TTT \ Th tee r
AY AINA Mh | i
FINVE) amulet dee,
Scymnognathus whaitsi Broom.
Reconstruction of internal aspect of the left side of the snout cut through in the middle line. Internarial bar and ossification in the nasal septum unshaded and surrounded by a thick continuous line; anterior end of the pterygoid represented by a line of small crosses. Parts of palatine seen through other bones in broken line. Reconstructed from the sections of 49369, checked by R. 4052. & 2.
Thus the anterior part of the palate is essentially a flat plate of bone, whose middle part is cut out by a narrow but gradually widening groove which plunges steeply downward to the deeply sunk posterior margin of the posterior nares. This groove is divided into two by a narrow vertical septum, which descends nearly to the level of the general plane of the palate.
CLASSIFICATION OF THE THERIODONYTTIA. 55
There can be little doubt, especially when the conditions in Arctops and Gorgonops are considered, that the inner pair of pro- cesses which support the imternarial bar are the anterior ends of the pterygoids. It remains to be shown by other materiai whether the median internarial bone and the median vomer in the back of the palate are parts of the same bone or are, as is more probable, separated.
The strange way in which the median internarial bar rises as a thin but very deep septum from the much sunk posterior nares, nearly to the general level of the palate, seems to be only explicable if its ventral border supported the middle of a small soft secondary palate stretched between the maxille and the palatines.
I have already described the mode of articulation of the squamosal with the brain-case and with the fused quadrate and quadrato-jugal in Proc. Zool. Soc. 1914, p. 1034, fig. 6.
The squamosal above the level of the post-temporal fossa bows out backward, so as largely to increase the size of the dorsal opening of the temporal fossa. It thus makes the occiput very deeply cupped, the interparietal region being narrowed and the outer part of the tabular running nearly antero-posteriorly.
At the extreme postero-lateral corner of the skull, the squamosal turns sharply into a process passing forward and Inward in the zygomatic arch. This process is clasped by other bones both admesially and externally. One of these bones is the jugal. The other conceivably also jugal, but much more probably postorbital. A gap about 2 cm. long in both sides of the specimen prevents a definite decision on this point.
The squamosal at the corner is made of a very peculiar, extremely dense, though finely cancellous bone. This structure is found in this region in all Theriodonts I have examined,
LEPTOTRACHELUS EUPACHYGNATHUS, gen. et sp. nov.
Type: a skull and lower jaw, described in error as Seymno- gnathus whaitsi by the writer (Ann. & Mag. Nat. Hist. ser. 8, vol. x. p. 578, fig. 3, and Proc. Zool. Soc. 1914, pp. 1027, 1032, figs. 3, 4, & 5).
The material is a largely disarticulated skull varying in preservation, with one complete and one pavtially disarticulated ramus of the lower jaw. ‘The skull is represented by the brain- case, interorbital region, left nasal, lachrymal, prefrontal, jugal, and squamosal in natural articulation, the right jugal, lachrymal, and prefrontal in natural articulation, but separated from the skull, an isolated maxilla, and quadrate and quadrato-jugal.
The mode of articulation of the quadrate with the squamosal is clear, and with the perfect lower jaw gives the length of the skull and the position of the maxilla. The large articulated part of the skull gives practically all the dorsal and the posterior part of the lateral surface directly, The occiput is essentially
56 MR. D. M. 8S. WATSON ON THE
completely preserved. All the sutures except those of the pavietals with each other and the preparietal are well shown.
In text-fig. 14 it is probable that the anterior part of the snout is made a little too narrow.
I have already described and figured the basicranial and otic regions, the occiput, and the interior of the brain-case.
Text-figure 14,
Leptotrachelus eupachygnathus, gen. et sp.nov. Type-skull.
2
Dorsal aspect. X §.
The outside of the brain-case is illustrated in text-fig. 16. The foramen for the VIIth nerve lies just above and in front of the fenestra ovalis, opening downwards through the pro-otic. The
CLASSIFICATION OF THE THERTODONTIA. trigeminal ‘ foramen ”
57 dorsal in position.
lies considerably forward and is move It lies at the end of a Jong slit and is pre- sumably really only an incision and not a foramen.
The length
Text-figure 15,
aie
Leptotrachelus eupachygnathus.
Type-skull.
Right lateral aspect. X F.
Text-figure 16.
Hy)
4,
\\
i Abe LYE i, & | zy
For Vi. PBR VE Fen.Ov. B.Oc.
TLeptotrachelus eupachygnathus, Type-skull. Left lateral aspect of brain-case, the parts of the skull lateral to the post-temporal fossa being removed as in text-fig. 10.
of the slit is rendered uncertain by the fracture of the anterior end of this part of the brain-case.
Tn the part of the brain-case preserved there is no evidence of the large venous foramen
58 MR. D. M. S. WATSON ON THE
described above in Scymnognathus whaitsi. There is no trace of the great anterior projections of the basisphenoid which in Seymnognathus meet in median suture in advance of the pituitary.
There is an ethmoid, which, so far as its very incomplete exposure allows it to be seen, does not difter from that of Scymnognathus.
The squamosal of Leptotrachelus is remarkable for the great length of its lateral projection and the extreme suddenness of the postero-lateral corner. As in Seymnognathus its distal end is received between two bones, here almost certainly the jugal and postorbital.
The cup-shaped depression in the widened lower edge of the squamosal into which the head of the quadvrate fits is very narrow, not half the width of the projection of the squamosal.
The quadrate is a relatively large bone about 30 mm. high by 15 mm. wide; it forms a nearly parallel straight-sided figure, the lower edge being a little marked off by a groove and forming the articular: surface. The upper end is rounded and fits snugly into the hollow in the squamosal. The quadrato-jugal is fused with the articular margin of the quadrate; it then separates from that bone, leaving a small quadiate foramen, whilst farther dorsally it spreads out into a flat sheet of bone which covers the outer margin of the quadrate and laps over its posterior surface.
When articulated with the squamosal the quadrate and quadrato-jugal are largely visible from behind.
The maxilla of Leptotrachelus shows a single canine in use, with traces of the crown of a successional canine high up in the alveolus, and four cheek-teeth ; it is possible that there was really a fifth cheek-tooth.
LycosaurRvUs PARDALIS Owen, Cat. Foss. Rept. 1876, p. 15, pl. 14.
The type-skull of Lycosawrus pardalis was re-examined and discussed by Broom, Proc. Zool. Soc. 1911-12, p. 1079, who gave it a dental formula: 1. 5, c. 2, m. 4.
The type-skull (R. 1717, B.M.N.H.) from the Cistecephalus- zone (%) of the Sneeuberg 1s considerably crushed laterally, but has the anterior end of ae snout complete and well-preserved ; behind the canine on the left side the outer surface of the skull is complete to the orbit, the whole orbital margin is present and a bit of the edge of the parietal region. The other side is a weathered face which cuts further and further imto the skull until it so far crosses the middle line as to expose the admedian surface of the left epipterygoid and completely to remove the brain-case. The squamosals are completely destroyed. The right lower jaw is, however, nearly perfect, having suffered only the loss of the posterior part of the angular so as to expose the articular—the position of the quadrate is thus fixed. The parts of the skull remaining are quite well-preserved and show many sutures,
CLASSIFICATION OF THE THERIODONTIA. 59
It is obvious that the snout is short, high, and narrow, with no trace of the square section which occurs in all the Gorgonopsids deseribed above.
The tooth-bearing edge of the maxilla is curved and passes gently into that of the premaxilla without the step of Gorgonops
; : s or Scymnognathus. ‘here is, however, a diastema between the closely-set incisors and the canine.
There are clearly 5 incisors, 1 canine, and 4 or possibly 5 molar teeth. Thesmall canine recorded by Broom immediately in front of the large one does not exist on the well-preserved left side, and his views seem to have been founded on a small strip of tooth in this position on the right side, which is really an exposed portion of the lower canine. The maxilla is short and deep.
Text-figure 17.
Fe. Fr, Niet Guha
Lycosaurus pardalis Owen. Type-skull.
Reconstruction of the right lateral aspect, X 2. The parts represented in broken lines hypothetically restored.
The external nostril of Zycosaurus differs considerably from that of Gorgonops. It faces more laterally and is much larger ; it is no longer overhung by so large a corner of the nasal, although there is still a trace of the older structure.
The facial part of the septomaxilla is much smaller, and the foramen between that bone and the maxilla is not only smaller but opens more directly outward. The septomaxilla in front of it seems to be rounded and grooved. Finally, the internarial process of the premaxilla is longer and stands more vertically, so that the end of the snout is deeper and less rounded in side-view.
The interorbital region is narrow, the postfrontal being a narrow pointed strip, as in the skull of Arctognathus curvi-
60 MR. D. M. 8S. WATSON ON THE
mola subsequently described (text-fig. 18). The parietal region is obviously of the Gorgonopsid type and cannot be very wide, although its width cannot be determined with any pretence to accuracy.
ARCTOGNATHUS CURVIMOLA (Owen), Cat. Foss. Rept. 1876, p. 71, pl. 68.
The skull (No. 47339 B.M.N.H.) deseribed by Owen as Lyco- saurus curvimola was found with Dicynodon tigriceps i the Cistecephalus beds of the Kagaberg, near Bedford, 8. Africa. Its palate was developed by Mr. Hall and described by Prof. Seeley, Phil. Trans. B. 185. The skull was then examined by Dr. Broom, who noted that the parietal region seemed to be broad, and made for it the genus Arctognathus.
The actual preservation of this skull is good; but before it was buried the left maxilla and ectopterygoid, together with the bit of lower jaw in their vicinity, were separated from the rest of the head by a nearly plane split, moved outwards for about 15 mm. and there fixed in the sediment. How this very peculiar result was brought about is very difficult to understand, although tentative suggestions might be made.
Whilst lying at the surface the nodule containing the skull was exposed to weathering, which has cut down into it so as completely to remove the right squamosal, the parietal region beyond the middle line, and the postorbital bar.
Fracture has removed the occipital condyle and part of the paroccipital process, but has left the stapes and quadrate with the lower jaw in articulation on the right side. Enough of the occiput is left to make the structure clear. ‘The palate is well exposed and very well preserved, the right ramus of the mandible is perfect and weli-exposed.
On the dorsal surface of the parietal region the suture between the parietals and the pineal foramen are very well shown on a weathered face, which lies a little below the original dorsal surface; the right side of this region retains its natural surface and shows the structure clearly.
The skull is short, broad, and deep. The snout is rounded in section and terminates in front in the internarial premaxillary processes, which form the extreme front end of the skull over- hanging the oral margin.
The very large nostril faces largely outward and is not over- hung by an outstanding corner of the nasal. The septomaxilla is small, and the foramen between it and the maxilla very small.
The interorbital width is considerable, but the orbits look upward and forward as largely as outward. The frontal does enter into the orbital margin, but only throygh a short distance The postfrontal is a narrow strip of bone wedged in between the frontal and the postorbital.
No trace of a preparietal is to be seen on the parts preserved,
CLASSIFICATION OF THE THERIODONTIA. 61
the median suture is clearly shown from the front of the pineal foramen to a point between the frontals, and the well-marked suture between the frontal and parietal passes very little in advance of the pineal opening. These sutures are, however, exposed at a plane below the orginal dorsal surface, and there is a remote possibility which cannot, although very improbable, be entirely excluded, that the preparietal was represented by a
Text-figure 18.
Arctognathus curvimola Owen. ‘Type-skull.
Restoration of the dorsal aspect, the parts in broken lines being hypothetically restored.
minute scale of bone lying on the dorsal surface. ‘The parietal region 1s about as wide as the interorbital.
The maxilla is short and deep, its co aA margin 1s much curved and passes smoothly with no trace of a step into that of the premayilla, The canines appear not to be completely erupted, and the four small cheek-teeth are also not very firmly
62 MR. D. M. 8S. WATSON ON THE
planted. The four incisors, though powerful, are not so dispro- portionately large as they are in earlier Gorgonopsids.
The palate of Arctognathus is very well-preserved, but its anterior end and two strips along the maxille are concealed by unremoved matrix and by the lower jaw.
The basioccipital is broken off through the vagal foramen, where it is thin and not very wide. The posterior part of the
Text-figure 19.
Arctognathus curvimola (Owen). Type-skull.
The palate, X 3. Stippled area covered by matrix and the lower jaw. Parts in dotted lines hypothetical. Ae A, direction of the section of ‘‘ Lycosaurus tigrinus,” text-fig. 20. St., stapes.
basisphenoid forms a triangular area with raised lateral margins, representing the tubera of earlier forms. Above the edges the sides of the bone are flat and vertical, posteriorly they terminate in the region of the fenestiz ovales, these openings beimg con- cealed by the foot of the stapes. Anteriorly these vertical sides
of the basisphenoid approach together until they are only
CLASSIFICATION OF THE THERIODON'TIA, 63
separated by a narrow ridge which runs forward to the palate proper. From the vertical sides of the basisphenoid horizontal processes arise; these basipterygoid processes support the ptery- goids. From their articulation with the basisphenoids the pterygoids pass backward towards the quadrates, but do not articulate with those bones, as they appear to terminate in free points before reaching them. The pterygoids pass forward, forming with the median ridge which continues the basisphenoid a bar whose ventral surface is almost cylindrical, broken only by the median fillet. At the hinder end of the palate the pterygoids suddenly widen, forming very deep powerful flanges. This part of the bone has a transverse suture with the ectopterygoid. Medially the two pterygoids meet in a visible suture which lies at the bottom of a small depression. ‘his suture soon terminates at the brim of a much deeper and more sharply-marked hollow, which, as it passes forward, widens and is converted into a deep open groove forming anteriorly the whole roof of the much vaulted palate. Throughout its extent this groove has well-marked, indeed often vertical, sides. Anteriorly this groove is divided into two by a ridge which rises from its surface. At about the level of the last maxillary tooth this groove is bounded by roughened areas of bone, which appear to have borne teeth. These areas are undoubtedly on the pterygoids and are separated by visible sutures from the palatines, which le laterally to the pterygoids in front of the ectopterygoids. Further forward these sutures, which form the inner border of the palatines, approach one another and descend into the groove, so that its side-walls are in front formed by the palatine. The ectopterygoids are separated from the palatines by visible sutures.
There is no trace of a suture down the mid-line of the groove, and its roof seems to be formed by a median bone, which terminates at the sudden end of the groove and must be bounded by sutures with the pterygoids along its edges ; of these presumed sutures nothing can be seen in this specimen.
The type-specimen of Lycosaurus tigrinus Owen seems to throw light on the structure of the palate of Arctognathus curvimola.
It consists of a fragment of a snout, broken off through the premaxille in front and by an oblique fracture on the left side, but showing much of the right maxilla. It has been so developed as to show a small strip of the surface of the right palatine and shows a section of the palate on the hinder end. ‘This species is referred by Broom to a new genus Arectosuchus, and said to have a dental formula, i. 5, ¢c. 1, m. 4 ov 5, representing a much more primitive type of Theriodont than Arctognathus. The type- specimen only shows two incisors, a canine, and a few cheek- teeth, and it seems certain that Broom examined and used for his description a snout of Seymnognathus whaitsi which Lydekker had referred to Z. tigrinus.
Except in the larger size and somewhat different direction of its canine, the type-specimen of ZL. tigrinws seems to agree
64 MR. D. M. S. WATSON ON THE
exactly in size and every point which can be compared with A. curvimola. The section of the palate shown on its posterior fracture is represented in text-fig. 20.
There is a median element bearing a high dorsal ridge, now detached, with a very deep groove on its mid-ventral surface and earried out laterally in a long wing, which is overlapped by the pterygoid. This bone bears a powerful irregular roughened projection carrying small teeth: laterally its surface is smooth, and is continued to the hinder end of the maxilla by that of the ectopterygoid. he two bones scarcely meet, but are joined together by a thin film of bone, undoubtedly the palatine, which covers their dorsal surfaces.
Text-figure 20.
Aretognathus. Type-specimen of Lycosaurus tigrinus Owen. X 5. A) } iy 3
Obliquely transverse section as a plane corresponding to A...... A in text-fig. 19.
If this section be compared with that which the palate of Arctognathus would present if cut along the line A~A, there can be no doubt of the close aftinity—indeed, specific identity—of the two forms, for even the possible measurements are in very close agreement.
Thus we have confirmation for the view that the roof of the median groove in the palate of Arctognathus is formed by a median vomer.
The epipterygoid of the type-specimen of A. curvimola 1s shown to meet the parietal in a long suture, exactly as does that of Diademodon.
The preceding series of description is based on the more complete and satisfactory remains of Gorgonopsids in the British Museum, largely Hndothiodon-zone forms. Of recent years Broom and Haughton, either independently or together, have described many complete Gorgonopsid skulls, chiefly from the Cistecephalus-zone. ‘They have, however, never given so complete an account of any form as that of Seymnognathus included in this paper, and it is seldom that they have given more than one
CLASSIFICATION OF THE THERIODONTIA. 65
or, at most, two drawings of any one skull. Thus it is difficult to carry out any detailed discussion of the mutual relations of the known Gorgonopsids,
In order to discuss with any satisfaction the classification of a group, it is necessary to know the main outlines of its history, to understand the direction of the advances which make the struc- ture of all late members of it differ from their ancestors, and to work out any adaptive modifications which characterize its different branches.
It is now generally agreed that the Gorgonopsids include the ancestors of the Cynognathide, and that the Pelycosaurs are a group which includes self-contained lateral branches springing from the very base of the stem of the mammal-like Reptiles. Thus by comparing the two extreme terms, Varanosaurus and Diademodon, we can gain at once a knowledge of the advances in structure which have occurred in the Anomodonts, and on the assumption that these changes have proceeded regularly we can determine the trend of advance during the evolution of the group. Discussion of intermediate forms will then enable us to decide whether this trend really expresses a true view of the mode of evolution, or whether the actual observed differences between the extremes represent the result of a series of fortuitous changes of indeterminate direction.
The work of Broili, of Case, of Williston, and the present writer has led to the view that Varanosaurus is the most primitive known Pelycosaur, forming a morphological ancestor to Dimetrodon, through a Deiopews-like form. The view that Diademodon or Trirachodon is the most advanced of known Anomodonts results from the work of Seeley and Broom.
The differences between the skull of Diademodon and Varano- SaUrUs are :—
In General Shape.
In Varanosaurus the snout is very long, square-cut in section, and roomy, compared with the rest of skull, with lateral nostrils and a long straight tooth-row. The large orbits are entirely laterally directed. The smail temporal fossa lies entirely on the side of the skull and is almost hidden from above by the very broad parietal region. The occiput slopes forward, but is not deeply cupped. The sides of the skull are nearly straight. The skull is higher than wide.
In Diademodon the snout is short, small in volume, rounded in section, with nostrils looking more forward than laterally. The tooth-row is short and curved The orbit is comparatively small and looks very largely forward. ‘The temporal fossa is very large, lies entirely on the top of the skull, and is not visible from the side, the parietal region being drawn up into a narrow crest. The occiput slopes «a little forward and is deeply cupped. The sides of the skull gradually approach one another to the orbits
Proc. Zoou. Soc.—1921, No. V. 5
66 MR. D. M. 8S. WATSON ON THE
but their direction is then changed as they form the slender snout. The skull is much wider than high.
In the Brain-case.
[The structure of the anterior face of the pro-otic and supra- occipital is not known in Varanosaurus and other regions are not very well shown. The following account of the Pelycosaurs is based on Deiopeus and Dimetrodon. |
In Pelycosaurs the basioccipital is thick, ending in a large rounded condyle. The large fenestrz ovales are placed on the bottom of the skull, far out at the side of the deep well-developed tubera. ‘The paroccipital process is short and slender, supporting the squamosal and touching the tabular; it les well above the lower surface of the skull. The pro-otic is small, its anterior face in no way overhanging the notch for the fifth nerve. The supra- occipital is entirely plate-like, not forming a roof over the brain in advance of the Vth nerve. The basisphenoid is massive, forming a sloping floor to the posterior part of the brain-case. It bears definite Sphenodou-like basipterygoid processes, anteriorly it is in Varanosaurus continued forward by a long channel-shaped parasphenoid.
The parietal does not form any part of the side-walls of the biain-case. ‘The epipterygoid is a slender rod of circular section.
The whole brain-cavity is very small in comparison with the size of the skull.
In Diademodon, on the other hand, the basioccipital is small and plays at most a subsidiary part im the pair of occipital con- dyles. The small fenestree ovales are placed on the bottom of the skull, not very far separated. Basisphenoidal tubera are repre- sented merely by the edges of the triangular lower face of the basisphenoid. The paroccipital is a long powerful process sup- porting the squamosal and touched by the tabular; it lies on the lower surface of the skull.
The pro-otic is large, being carried forward by a great process which completely overhangs the trigeminal foramen.
The supraoccipital is produced forwards by two wings, which cover and form side-walls to a great deal of the brain-cavity in advance of the Vth nerve.
The basisphenoid is a small bone forming a nearly horizontal floor to the brain-case. It has small lateral basipterygoid pro- cesses with the pterygoids attached to thei flat lower surfaces ; anteriorly it is carried forward by a slender process which reaches the palate and there spreads out into a broad vomer in the roof of the posterior part of the nasc-pharyngeal ducts.
The parietal forms a good deal of the side-wall of the brain- case. ‘The epipterygoid isa flat plate forming the side-wall of the brain-case for some distance and articulating with the anterior edges of the pro-otic. The brain-cavity is relatively very large.
The ear of a Pelyeosaur, so far as can be inferred from the bone which housed it, lies low down on the side of the brain-ease,
CLASSIFICATION OF THE THERIODONTTA. 67
has small simple semicircular canals, and has a cochlea which leaves no evidence of its existence on the bones. ‘lhe fenestra rotunda is represented by a notch on the ridge, which in the bony skull separates the vestibular cavity from the vagal foramen, and thus opens inside the brain-eavity. The stapes is always very large and is perforated, the fenestra ovalis being a large irregular hole. There is no groove for the external auditory meatus.
In Diademodon the inner ear retains its original position low down on the side of the brain-case and still shows only simple semicircular canals. It has, however, a well-defined cochlea housed in a erypt passing forward and inward, and curved forward through about a quadrant of a cirele. The fenestra rotunda is a complete foramen, which opens indeed into the vagal foramen, but does so on the outer surface of the neural cranium, exactly as if does in the young Ornithorhynchus.
The stapes, although still of good size, is much smaller than in Pelycosaurs, and the fenestra ovalis is a neat round hole of small size. The external auditory meatus is housed by a deep . groove.
The nose of Diademodon occupies a smaller space than that of Dimetrodon, but the area of its sensory epithelium seems to have been increased by a great development of turbinal cartilage, now only represented by a series of ridges, on the inner surface of the nasals and prefrontals which once supported them. Nothing of the kind occurs in Pelycosaurs,
Many other features in the nose of the Anomodonts can only be discussed in connection with the septomaxilla, palate, etc., and then only im a detailed discussion of individual forms.
The Roof of the Skull.
In Varanosaurus the parietals ave short, very broad, and with the pineal foramen very far back. Their edges are separated from the temporal fossee by a union of the postorbital and squamosal. There is a large postfrontal lying on the roof of the skull. The frontal is a large bone always entering into the orbital margin. The prefrontals are large bones, almost equally divided between the dorsal and lateral surfaces of the skull, each bearing a depression on the outer face just in front of the orbit. The nasals are narrow slips of bones. There is a small supratempoval,
In Diademodon the pavietals are long, very narrow, and with the pineal foramen between their anterior ends. ‘They form the inner margins of the temporal fosse for a very long way, the squamosal and postorbital being widely separated. ‘There is no postfrontal. The frontal is a small bone, not entering the orbital margin. ‘The prefrontals are small bones on the rounded snout, with no depression in front of the orbit. The nasals are wide, especially posteriorly. There is no sjpuniioutypant ls
D
68 MR. D. M. S. WATSON ON 'THE
In side-view the skull of Varanosaurus shows a long shallow maxilla, completely separated from the nasal by the long lachrymal extending from the orbit to the septomaxilla. There is no very marked specialization of the dentition, all the teeth from the premaxilla backward being similar in form and not very dis- similar in size. The quadrato-jugal is exposed on the side-wall of the skull and the jugal stops considerably before the quadrate.
Diademodon has a short deep maxilla reaching the nasal in a long suture. The lachrymal is a small short bone. The dentition 1S fully divided into incisor, canine, ‘‘ premolar,” and “ molar teeth.”
The quadrato-jugal no longer appears on the surface of the skull and the jugal extends back to its extreme hinder end.
The suspensorium of Varanosaurus consists of a large quadrate with a definite pterygoid wing, whose posterior surface J 1s covered by the pterygoid... The outer edge of the quadrate is attached to the quadrato-jugal, there being no quadrate foramen. The upper part of the posterior surface of the quadrate is covered by the squamosal, that bone passing so far inwards as to touch the pterygoid.
In Diademodon the quadrate is a very small bone, either with or without a pterygoid wing, but in no case articulating with the pterygoid. ‘The outer edge of the quadrate is fused with the quadrato-jugal, from which it is separated only by a small foramen, the articular surface being formed about equally by either bone. The whole posterior surface of the joint bone is covered by the very large squamosal, which extends down to the condylar edge.
The primitive Pelycosaur palate has the following characters :— The pterygoid is a triradiate bone, articulating “by a movable facet with the basipterygoid process, from which point the quadrate ramus rises and runs backward as a vertically placed sheet of bone, passing behind the quadrate. The lateral wing of the pterygoid passes directly outward from the region of the basipterygoid and terminates in the usual flange.
The anterior part of the pterygoid forms a large part of the essentially flat palatal surface and articulates with ‘the prevomer. It meets its fellow in median suture in Varanosaurus. he dorsal surface of the pterygoid is raised into a ridge near the middle line of the skull. In later forms (Dimetr afl, e. g.), the ridge is much exaggerated and its median surface passes smoothly into the ventral surface. The palatines are small flat bones. The prevomers are distinct. The anterior end of the palate is not known in any primitive Pelycosaur, but from the conditions in later forms there is no doubt that the posterior nares were small and lay in the general plane of the rest of the palate, which was essentially Ane In such later Pelycosaurs as Dimetrodon, owing to the step in the lower edge of the maxilla, the palate is considerably vaulted, and the posterior nares lie above the level of the cheek-teeth.
In Diademodon the pterygoid articulates by a rigid suture with
CLASSIFICATION OF THE THERIODONTTA. 69
the lower surface of the basipterygoid process, and there is no quadrate ramus, the bone terminating at its attachment. The transverse ramus does not arise from the basipterygoid region, but very much further forward, the posterior part of the bone being a slender strip, which is united with its fellow and the parasphenoid to form a slender bar.
The transverse ramus arises very suddenly from this bar, the bone being drawn downward into deep and very powerful flanges.
There is no anterior vamus, the bone ending in a transverse suture with the palatine at the region where it joins the jugal.
The transverse bone is very small and is not included in the flange at the foot of which it lies.
The palatine is a very large bone, forming a great deal of the posterior part of the palate, then turning downward to form the lateral wall of the posterior part of the nasopharyngeal duct, and, finally, developing a secondary plate, which forms a floor to that passage.
The two palatines are separated by a median vomer, which forms the roof of the nasopharyngeal passage, apparently ter- minating behind in a pointed slip separating the anterior ends of the pterygoids, but really passing backward to the basisphenoid.
The prevomers seem to have vanished entirely.
The maxillz send inward secondary plates, which continue those of the palatine forward. The premaxille have palatal processes, which pass dorsally to the secondary plates of the maxille and touch the anterior end of an ossification in the nasal septum, viz., a mesethmoid.
In Varanosaurus the epipterygoid is a slender rod rising vertically from the dorsal surface of the pterygoid just in advance of the basipterygoid articulation.
In Diademodon the epipterygoid is a large flat sheet of bone forming a side-wall to the brain-case and articulating by a very long suture with the parietal and frontal above, having a suture with the pro-otic behind, articulating with the basipterygoid process below, and ending in a suture with the pterygoid. Behind the basipterygoid and below the point of exit of the maxillary, mandibular, and motor portions of the fifth nerve, the epipterygoid is continued backward by a process occupying the position of a quadrate ramus of the pterygoid. The ramus in certain species articulates with the front face of the quadrate.
The preceding pages record the more important differences between the most primitive and the most advanced known Anomodont; they bring out the direction of the evolutionary advances and show how enormous is the structural gap between them, a gap represented in time by the relatively small interval between the bottom of the Permian and the middle of the Triassic system.
It remains to show how completely this morphological gap can be bridged by the material available. Although, as Case and Williston have repeatedly and emphatically pointed out, the Pely- cosaurs are a self-contained group dying out with Dimetrodon and
70 MR. D. M. S. WATSON ON THE
Edaphosaurus, they show evolutionary changes which are in the main in the same direction as these which lead from Varanosaurus to Diademodon, coupled, of course, with many individual speciali- zations. Although it is not essential for the purpose of this paper, it is, I think, useful to point out certain of the more striking of these advances, using Varanosaurus, Deiopeus, and Dimetrodon as the series of forms. These animals lived side by side, and this series is only a morphological one.
In general shape Dimetrodon shows an advance on Varano- saurus in that the snout is much deepened, is square in section only immediately in front of the orbit, and is, in general, wedge- shaped with a rounded dorsal edge. The par ‘ietal region 1s narrower, and leaves the temporal fossee visible from above. The oceiput is more vertical. In the brain-case Dimetrodon shows an advance over Deiopeus in that the basioccipital is thinner, the basisphenoidal tubera smaller, and the paroccipital process larger. The anterior margin of the pro-otic lies furtherin advance of the internal auditory meatus. The brain-cavity is considerably deeper and wider posteriorly. The fenestra ovalis of Dimetrodon is smaller than that of Deiopews and the stapes lighter. The roof of the skull of Dimetrodon differs from Varanosaurus in the following ways:—the parietals are Jess wide and the pineal foramen further forward. The postorbital is visible from above. The pair of frontals have acquired a cruciform shape owing to a widening of the interorbital surface. Deiopeus provides an exact intermediate, the increased width of the interorbital surface having arisen by an increase in size of the pre- and post-frontals, so as to leave a gap which is filled up by a special process of the frontal.
In side-view the skull of Dimetrodon shows a shortened and deepened maxilla touching the nasal in a short suture. The dentition is sharply divided into incisors and cheek-teeth by a diastema. The third maxillary tooth is much larger than the first two, and the lower border of its socket lies well below the dentigerous border of the premaxilla.
The lachrymal does not reach the septomaxilla. The orbit is placed high up in the skull.
It seems probable that the deepening of the maxilla and the “step”? depend on the necessity of finding room for the roots of, and the development of, replacing teeth for the greatly lengthened maxillary teeth.
The condition of the canine may depend on the following con- siderations:—A. large canine in the upper jaw presupposes a similar tooth in the lower jaw; such teeth, which are designed for killing animals, are most useful in the front of the mouth. The lower jaw, as a whole, bites inside the upper jaw. The first tooth of the lower jaw cannot be much enlarged, because of the difficulty of making a pit for its reception near the middle Ime in the palatal process of the premaxilla; hence the lower canine cannot be quite at the end of the jaw. A large lower canine almost involves a diastema in the upper jaw for it to bite into, because
CLASSIFICATION OF THE TILERIODONTIA, 71
Text-figure 21.
Series of dvawimgs of the right lateral aspect of Pelycosaur skulls, reduced to the same length.
A. Varanosaurus acutirostris Broili, restoved from the type-skull in Munich, partly after Broili. B. Deiopeus leptocephalus Cope, restored from the type-skull in the American Museum. C. Sphenacodon ferow Marsh, after Williston. D. Dimetrodon gigas Case, from a photograph published by Case.
72 MR. D. M. S. WATSON ON THE
being laterally placed, the formation of a pit in the palate fer its reception so narrows the dentigerous part of the maxilla outside it as to leave no room for a tooth. The same factors will render difficult any great enlargement of the next tooth, and the upper canine thus comes to lie behind the diastema and separated from it by at least one small tooth. Considering the mechanics of the whole arrangement, it appears useful to make the dentition more or less symmetrical about the diastema by enlarging a pre- maxillary tooth to correspond with the canine, so that the single lower canine forces the prey into the gap between two large upper teeth. The dentition so designed is realized in Dimetrodon.
Text-figure 22.
Re es mn ee
A. Superimposed outlines of sagittal sections of the brain-cases of Deiopeus in broken line and Dimetrodon in continuous line reduced to the same length, to show the thinning of the basis cranii, the enlargement of the brain-cavity, and the forward growth of the pro-otic.
B. Superimposed outlines of sagittal sections of the brain-cases of Leptotra- chelus in broken line and Diademodon in continuous line reduced to the same length, to show: the thinning of the basis cranii, the forward growth of the pro-otic, the enormous increase of the cerebellar cavity, and the relatively slight growth of the cerebral region.
The great deepening of the maxilla demanded by the canine automatically squeezes out of existence the anterior part of the lachrymal.
Deiopeus and Ophiacodon provide an exact intermediate between
CLASSIFICATION OF THE THERIODONTIA. . 73
Varanosaurus and Dimetrodon in dentition, as Case has already shown.
In the palate Dimetrodon differs from Varanosaurus in that the transverse flanges of the pterygoids have moved much forward from the basipterygoid region. The condition in Deiopeus is not known. Thus many of the structural changes which separate the advanced from the primitive Pelycosaurs are in the same direction as the general advances of the Anomodonts from first to last.
The earliest known Gorgonopsid is Galesuchus gracilis Haugh- ton, from the Zapinocephalus-zone.
This skull I have not seen, but judge that it is so much weathered that the original shape of the squamosals cannot be seen. Only the dorsal aspect has been figured. The skull is very remarkable, differing much from all later Gorgonopsids and even more from Pelycosaurs. Its only primitive features seem to be the extremely sloping occiput (the apparent slope being possibly exaggerated), the high position of the foramen magnum and foramen jugulare, the large deep paroccipital processes, the great size of the frontal, and the lateral direction of the orbits. It is, however, so incompletely known that a full discussion of its affinities is impossible.
The most primitive known Gorgonopsid is Arctops. This re- tains as primitive features, which it shares with the Pelycosaurs :—~ the square section of the snout with a depression on the preorbital surface overhung by the prefrontal, the lateral direction of the orbits, the extreme parietal width, and the shortness of the parietals. The resemblances in the basicranial and otic regions have been discussed (P. Z. S. 1914, p. 1027).
The palate retains a primitive structure in the non-fusion of the prevomers.
The skull shows advances over Varanosaurus in the following ways :—Owing to the need of increasing the size of the temporal muscles the squamosal is bayed outward, a modification which makes the temporal fossa visible from above; this change not only allows of greater thickening of the temporal muscles during their contraction, a function which is believed by Gregory and Adams to be the factor which determines the origin of fenes- tration, but also enables the outer part of the temporal muscle to acquire a new origin on the upper edge and inner surface of the zygomatic arch, thereby establishing an independent masseter muscle. At the same time this widespread zygomatic arch passes much laterally to the quadrate and leaves that bone, with the quadrato-jugal attached to its outer margin, lying entirely within the back of the enlarged temporal fossa; these bones, having thus lost the support that they originally received from the junction of the quadrato-jugal with the jugal and squamosal by sutures, can only be adequately supported by a more powerful abutment on the paroccipital process and by an extension of the squamosai down their posterior surface.
At the same time the lateral extension of the squamosal renders
14 MR. D. M. S. WATSON ON THE
the back of the skull much wider than the neck, and makes the tympanic membrane lie much nearer the middle line than the side of the skull. As it is necessary to keep this membrane exposed to the outer air, any swelling of the neck will automatically lead to the formation of an external auditory meatus; the beginnings of this passage are seen in Arctops in a groove on the posterior surface of the squamosal, just outside the end of the paroccipital process.
On the vential surface Arctops has advanced over Varano- sawrus in the shift forward of the great pterygoidal flanges to a position far in advanee of the basipterygoid processes ; this change results in a further great enlargement of the cavity for the temporal muscles, and allows the development of great pterygoidal muscles with an insertion on the dorsal surface of the palate.
This shift forward of the flanges has occurred in Dumetrodon, but the conditions in Arctops differ from those in the earlier form in the fusion of the posterior parts of the pterygoids and parasphenoid into a massive ridged girder. This change adds greatiy to the strength and rigidity of the skull, but its details cannot readily be explained by mechanical considerations; the most important of these is the replacement of normal basiptery- goid processes by the laterally directed flat lappets which occur in all Theriodonts.
In the palate itself the more important changes are the development of a median groove, a necessary preliminary to the establishment of a secondary palate, which is brought about by that change in the dentition involving the development of a ‘step ” between the maxillary and incisor teeth which has been discussed under Dimetrodon, and the extreme posterior position of the hinder ends of the posterior nares; this latter change is itself probably to be associated with the incipient secondary palate, leading as it does to a longer air-passage whose posterior end is not so easily closed by the presence of food in the anterior part of the mouth.
Another advance in Arctops is the more vertical position of the occiput.
Glorgonops is in some ways as primitive as Arctops, with which it shares very broad parietal and interorbital regions and a square sectioned snout. The orbit faces laterally in both forms, and each has a remarkably broad interparietal, a feature in which they resemble Deinocephalians.
Gorgonops has a pair of large frontals, which are cruciform in plan exactly as in the later Pelycosaur.
The prefrontal is a large bone which overhangs a well-marked depression on the preorbital surface.
Gorgonops shows advances over Varanosawrus which, so far as the parts are known, include all those which occur in drctops, with the following additions :—Lhe external nostril in Gorgonops is much complicated by the great development of the septomaxilla and the foramen behind it. This foramen, first recognised hy
CLASSIFICATION OF 'THE THERIODONTTA. 75
Case in Dimetrodon, occurs in all the more primitive Anomodonts and is still of uncertain function. In all Pelycosaurs the septo- maxilla is a small bone resting on the maxilla and premaxilla at the back of the nostril, being touched by the nasal and forming with the other bones the aie amen, which I propose to call the septomaxillary foramen.
In Dimetrodon the lower edge of the septomaxilla, where it rests on the maxilla, is turned inwards and forms a partial floor to the nasal passage. The anterior border of the septomaxilla is provided with a process which partially divides the external nostril into a lower and an upper part.
It is probable that the process on the anterior edge of the septomaxilla is associated with the original turbinal, simply forming the anterior end of that ridge. iia the living lizards and snakes, “Whe septomaxilla lies inside the nostril as it does in the Captorhinids, the collateral ancestors of the Pelycosaurs; it has in them a characteristic and uniform situation, in that it is ossified in the membrane dividing the main nasal cavity from Jacobson’s organ, running nearly horizontally from the maxilla to the cartilaginous nasal septum.
In evomotionts I have only heard one possible suggestion for the function of the septomaxillary foramen, that it ser rved as an outflow for the ductus naso-lachrymalis, the liquid poured out from it serving to keep the muzzle wet asin Artiodactyls. This view is in harmony with the known position of the duct in early amphibia and reptiles. It, however, does not afford any satis- factory explanation of the eveat size of the foramen in Gor gonops.
The very peculiar conditions in the Deinocephalian Jormo- saurus (Proc. Zool. Soc. 1914, p. 757, figs. 1 & 2) suggest another explanation. In this animal the ordinary external nostril, which in early reptiles always lies between the premaxilla, the septo- maxilla, and nasal, appears to be represented by a minute foramen between the septomaxilla and the nasal. The large opening which is the functional nostril seems to be really a septomaxillary foramen, as it lies between the premaxilla, the maxilla, and septomaxilla, a situation which is never occupied by the ordinary nostril in early reptiles, but agrees with that of the septo- maxillary foramen in the earlier Vheriodonts. Thus this foramen must be of the nature of a nostril. The characteristic position of the septomaxilla in Squamates suggests that the foramen leads into Jacobson’s organ, and it will follow that that organ was the functional olfactory organ of Mormosaurus; the shallowness and small size of the upper part of the nasal cavity, which distinguishes Mormosaurus from such Deinocephalia as J/oschops with a normal septomaxillary foramen and nostril, can thus be accounted for.
The advances over Varanosaurus which are shown in the nose of Gorgonops ave:—(1) the direction of the nostril forwards instead of laterally, a change which renders the appreciation of odours coming from the direction in which the animal is pro-
76 MR. D. M. 8. WATSON ON 'THE
ceeding more delicate, because owing to a Pitot effect more air will be driven into the nasal cavity; (2) a great increase in the size of the septomaxillary foramen, possibly associated with a further elaboration of Jacobson’s organ ; (3) a great increase in the size of the facial part of the septomaxilla—this may be due to purely mechanical reasons.
Another advance very clearly shown in Gorgonops is a great deepening of the maxilla and a concurrent reduction of the lachrymal, the prefrontal showing little reduction.
The palate of Gorgonops is advanced in the great size of the internal nares, in the width, depth, and backward extension of the median groove, in the internarial bar being single, and in the occurrence of a median vomer in the back of the palate.
The very large size of the pterygoids and the forward position of the roughened and possibly tooth-bearing areas on these bones are primitive features.
The basicranial region shows no structural detail.
Scymnognathus whaitsi shows many resemblances to Gorgonops 1m its snout.
It shows advances over Avctops in the thinner basioccipital, smaller basisphenoidal tubera, and less massive paroccipital pro- CeSses.
The brain-case is advanced over that of the Pelycosaur Dimetrodon in the great forward extension of the pro-otice and supraoccipital and the junction of the latter bone with the epipterygoid ; a remarkable feature is the forward process of the basisphenoid, which forms a floor to the brain-case in advance of the pituitary fossa.
The most striking advances over Arctops are the great redue- tion in width of the parietal region, the lengthening of the pavietals, and especially the enormous increase in spread of the squamosals. The turning backward of the upper part of the squamosal at the posterior margin of the temporal fossa makes that opening even larger, and increases the length of certain fibres of the temporal muscles.
So far as known, similar differences separate Scymnognathus from Gorgonops, the latter genus having much larger frontals than the former.
By the great expansion of the width of the back of the skull, the orbits of Scymnognathus ave made to look partly forward.
Another small but important advance in Scymnognathus is that certain fibres of the temporal muscle have secured an origin from the dorsal surface of the parietal region.
Seymnognathus is probably less advanced than Arctops and Gorgonops in its less vertical occiput. In the palate Seymno- gnathus is probably less advanced than Gorgonops in the small size of the median groove, and its restriction to the anterior part of the palate and to a narrow space round the hinder end of the posterior nares.
The incompletely known Leptotrachelus shows an important
CLASSIFICATION OF THE THERIODONTIA, re
stage in the advance in structure of the basieranial region, already discussed in P.Z.S8. 1914, p. 1027, fies. 3 & 4; it is in this region more advanced than any other known Hndothiodon- zone Gorgonopsid. It retains as primitive features the very large quadrate, large postfrontal and frontal, and a sloping occiput. Thus the “Yndothiodon-zone Gorgonopsids show definite ad- vances over the Pelycosaurs in the direction of Diademodon. Kach form is advanced in éertain features whilst retaining a more primitive structure in others, so that an imaginary animal, built up by throwing together the most advanced features found in all the actual animals, would be far more advanced than any one is on the average; although in no point would it be more advanced than a known form. tn fact, the evidence existing here, small though it is, suggests that tihee is a limit to the total amount of advance possible to the members of a group in a given time, and that these changes may be distributed either over the whole animal or concentrated on a definite region, which will then present a structure of much more advanced type than is found in allied contemporaneous forms. A somewhat similar conclusion seems to have been reached by W. D. Matthew from the study of the more abundant material of fossil mammals.
Discussion of the Gorgonopsids of the Cistecephalus-zone is rendered difficult by two factors—the incomplete descriptions and insufficient figures of many of the perfect skulls in S. Africa and New York, and the fact that the Cistecephalus-zone is a long one and that we do not know the relative ages of the Gorgonopsids from it. It will appear from the evidence to be brought forward in this paper that the forms from Dunedin and Nieuweveld localities are early, those from New Bethesda and the Kagaberg which are associated with Dicynodon tigriceps considerably later in time. There is, however, no stratigraphical evidence that this is so.
From the Cistecephalus-zone Broom and Haughton have described several forms as species of Scymnognathus—s. tigriceps B. & H., S. parvus Br., S. minor Bv., S. angusticeps Br., S. serra- tidens Tau., are all from the Nieuweveld. These forms may very possibly be congeneric; they agree with Scymnognathus in having 1. 5, c. 1, m. 4-5, but quite certainly do not belong to that genus. They differ from Scymnognathus whaitsi in the following characters :—
The snout is very much deeper, its anterior end instead of being rounded is vertical (¢f. Broom, P. Z.8. 1913, p. 225, pl. 36), the external nostril is much larger, the septomaxillary foramen smaller. The anterior end of the nasal does not fully overhang the nostril. ‘The top of the snout may be ridged, and the square section with a preorbital depression overhung by the prefrontal is entirely lost (cf. S. serratidens, Ann. South Afr, Mus. vol. xii. p. 89, pl. xii.). The snout is much shorter and the prefrontal in consequence smaller,
78 MR. D. M. 8S. WATSON ON THE
There is no step in the upper jaw, the curved tooth-bearing edge of the premaxilla passing smoothly into that of the maxilla. In_ 8. tigriceps thé squamosals are not nearly so much spread, the skull being much deeper in proportion to its width. If we may trust the existing description of a not very satisfactory prepara- tion, the palate of S. tigriceps differs from that of S. whaitst in the loss of the anteor projection of the pterygoid and the great extension of the palatines. On the other hand, judging from the description by Haughton of its endocranial surface, the brain-case of S. tigriceps may have greatly resembled that of S. whaits.
Thus the Cistecephalus-zone animals referred to Seymno- gnathus do not belong to that genus, but differ from it by a series of advances which will be seen to be all in the direction leading to Diademodon. Certain of these species appear to resemble Lycosaurus pardalis considerably, agreeing with that animal in dentition, the short high snout with a rounded dorsal surface, the large nostril, the vertical imternarial bar, the small exposure of the septomaxilla, the absence of a step in the upper jaw, the short and deep maxilla, and the small prefrontal. Ail of them, however, seem to retain a large postfrontal bone.
Two other remarkable forms, apparently from the lower part of the Cistecephalus-zone, Scylacops capensis and Corgognathus longifrons, ave of interest because they strongly recall Hndothiodon- zone forms.
Gorgognathus with its Spaaneprenneel yp Jong low snout somewhat resembles Scymnognathus whaitsi, and its ver y broad interorbita] and intertemporal surfaces agree soratlh Glorgonops. It is, however, advanced in the following characters :— The loss of the step in the jaw, the rounded snout, and especially the vertical occiput. Haughton has pointed out another advanced feature in the structure of the basicvanial region. Seylacops is a small unusual form with a low broad snout: it is advanced in the exclusion of the frontal from the orbital margin, in the rather vertical occi- put, in the loss of the step in the upper Jaw, and especially in the loss of the anterior ramus of the pterygoid: it appears to retain a rather primitive Gorgonops-like nose and has only small temporal fossee. Broom’s figure of the occiput suggests that it is advanced in the shallowness of the paroccipital processes. [It is probable that the fragment of a Gorgonopsid skull which I described (Ann. & Mag. Nat. Hist. 1913, vol. xi. p. 65, figs. 1-4) belongs, if not to Seylucops, at any rate to a clos ely ailucdl ton |
Arctognathus curvimola is a far more advanced form than any so far discussed in this paper ; 1t pr comma ly comes from a higher horizon in the Cistecephalus-zone than Gorgognathus, oe,” Thi shows advances in the following features :—The snout is short, narrower than the orbital region, rounded over the mid-line. The nostrils are very Jarge and the septomaxillary foramen smal]. The nasals do not overhang in front. The interorbital and intertemporal surfaces are narrow, the orbits facing outwards,
CLASSIFICATION OF THE THERIODONITTA. 79
upwards, and a little forwards. The postfrontal is very small, the preparietal is absent. ‘The maxilla is very short and deep, there is no step in the upper jaw. ‘The prefrontal is short and probably small. I have already shown that the basicranial and otic regions are very advanced (Proc. Zool. Soc. 1914, p- 1028). The epipterygoids are widened and flat, very much as in Diademodon. The posterior end of the quadrate ramus of the pterygoid no longer reaches the quadrate. The pterygo- pavasphenoidal girder, instead of having a flat ventral surface from which a deep median crest rises, is rounded, with the crest represented by a low fillet.
The palate is most conveniently compared with that of Gorgonops, which represents an earlier stage leading to it.
The great median groove is deepened and its roof is entirely formed by a median vomer, which presumably represents a forward growth of the posterior median bone of the Gorgonops palate. Anteriorly the ridge rising from the vomer in <Arcto- gnathus suggests that there was a soft secondary palate into which a secondary bony plate may have grown out in the concealed part of the palate.
The tooth-bearing roughened area of the anterior ramus of the pterygoid hes much further back than in Gor gonops, and the pterygoid no longer reaches the posterior nares.
The quadrate of dArctognathus is much smaller than that of Scymnognathus.
The conversion of Aretognathus into a Cynodont Tike 0 yno- gnathus demands only the following changes :—Still further thin- ning of the basis cranil, further reduction of the quadrate wing of the pterygoid, the development of a connection between the quadrate wing of the epipterygoid and the paroccipital ; further retraction of ane unterior ramus of the pterygoid, so as to reduce the roughened areas to a pair of small knobs on each side of the posterior end of the median groove; a little reduction of the ectopterygoid; the development of secondary plates from the maxille and palatines in the existing soft secondary palate ; the conversion of the narrow intertemporal area into a sagittal crest, to increase the length of the temporal muscles; the loss of the postfrontal, and a further reduction of the frontal and prefrontal, leading to an increase in size of the posterior part of the nasals. ‘These changes are all in the same direction as those which convert a Pelycosaur like Varanosaurus into a Theriodont like Gorgonops, and an animal like Gorgonops into a form like Arctognathus, and are, on the whole, smaller than those which ave necessary to carry out the earlier improvements ; in fact, Arcto- gnathus, which is technically a Gorgonopsid, is structurally closer to Cynognathus than it is to Gorgonops.
Amongst other advanced forms allied to the Gorgonopsids and coming from the Cistecephalus-zone are Cynosuchus and Whaitsia, which have both been excellently described, though not com- pletely figured, by Haughton.
80 MR. D. M. S. WATSON ON THE
Whaitsia is a remarkable form with a somewhat primitive basicranial region, and a palate which in general agrees with Gorgonops, but differs in the development of a special process passing out on each side of the internarial bar so as to divide each posterior nostril into two. {The meaning, morphology, and function of this arrangement are quite uncertain, the anterior vacuities are not exactly homologous with the anterior palatine incisions of mammals and Cynodonts, because the posterior border of these incisions is always formed by the anterior edge of the secondary plate of the maxilla.| Whactsia is very advanced in the reduction of the wide parietal region to a narrow sagittal crest, which characterizes it, and in the extreme reduction of the dentition.
The preceding discussion shows that the Gorgonopsids include a series of forms which exhibit in their skulls a gradual series of changes by which so primitive an animal as Arctops passes in- sensibly into a Cynognathid. It establishes clearly the existence of a series of evolutionary trends, which persist without change from the beginning of the Anomodonts in Varanosaurus to their end in Diademodon, and indeed to lead on to mammals. It remains to discuss the other primitive Theriodonts included in Broom’s order Therocephalia and the Deinocephalia, to see how far these evolutionary trends apply also to them, and to consider the relation of these forms to the Gorgonopsids, which are plainly the central group of the ‘Theriodonts.
No Therocephalian is at all well known, despite the very large number of forms which have been described. We know the dorsal and lateral surfaces of the skull in a good many forms (Seylacosaurus, Lycosaurus, Scaloposaurus, etc.), the palate 1s known more or less completely in others (Scylacosaurus, Seyn- nosaurus, Scaloposaurus, ete.). The basicranial region is known in no Therocephalian, neither has any occiput been figured. Haughton has described the brain-case of Alopecognathus, but his figure is not in all points (e.g., the character of the supra- occipital and the relations of the interparietal and parietal) very convincing.
The most important materials of Therocephala in the British Museum are the more or less complete skulls of Scaloposaurus from the Cistecephalus-zone and Scylocosaurus and Seymno- saurus watsoni from the T'apinocephalus-zone.
ScyMNOSAURUS WAtTSONT Broom, Proc. Zool. Soc. 1915, p. 169, fig. 6.
Lycosuchus? Watson, Proc. Zool. Soc. 1914, p. 10386, fig. 7.
Type: a skull with seven cervical vertebre in natural articu- lation, other vertebre and fragmentary limbs doubtfully associated. Tapinocephalus-zone, Uitkyk, Dist. Prince Albert, Cape Province.
The skull of the type is curiously preserved: it is embedded in a caleaveous nodule, which breaks with a conchoidal fracture and
CLASSIFICATION OF THE THERIODONTIA, 81
is so loaded with a very fine siliceous mud as to be glass-hard, completely blunting a carefully hard-tempered chisel after a single blow.
The skull is broken through along the plane of the palate, part of that structure adhering to each block. ‘he skull is then broken through by a split which passes through the brain-cavity and removes the whole left posterior corner of the skull behind the orbit. Finally, another spht traverses the occiput, part of that region adhering to each surface.
Where weathering has softened the matrix, very good pre- parations are easily made, and in these regions, especially where
Text-figure 25.
Qu. inlooe Oe. 1 B.de Civek
Scymnosaurus watsoni Broom. Type-skull.
Occipital aspect. 4.
the bone has been cleaned by weathering, the preservation 1s extraordinarily good. Development of the unweathered regions is a very ditticult and extremely slow and tedious process. Never- theless, I have been able to make a satisfactory preparation of the inner surface of the cranial cavity.
The occiput now shows nearly every detail of its structure, although a direct view of its posterior surface cannot be seen. Its outline is well shown and the posterior surfaces of the quad- rates and squamosals ave clean,
Dr. Broom’s figures give a good idea of the general shape, the structure of the dorsal and lateral aspects not being shown.
Proc. Zoo. Soc.—1921, No. VI. 6
82 MR. D. M. 8, WATSON ON THR
My former figure gives a good idea of the palate, whose struc- ture is well shown. It, however, does not clearly illustrate the exact mode of articulation of the quadrate to the squamosal and the structure of the extreme postero-lateral corner of the skull and the auditory groove. This inaccuracy, which is not of a very serious nature, was due to a misunderstanding by about 30° of the orientation of the detached left corner, which was at that time the better exposed.
The basioccipital condyle is largely concealed by the attached atlas, but is partly exposed from below and cut by fractures which give sections through it. It is rounded and nearly twice as wide as itis deep. It is shortand immediately in front of it, at a plane a little in front of the general occipital surface, lie the very broad and massive basisphenoidal tubera. These have a flat posterior surface overhung by the projecting exoccipitals, which are separated from them by the small vagal foramen and per- forated by small foramina for the XIIth nerves. The structure of the anterior part of the basisphenoid has already been described.
The paroccipital process is very massive; not only is it thick from back to front, but the small post-temporal fossa is placed high up so that the process is deep. Although the fenestra ovalis is not visible there can be no doubt, from consideration of the general structure, that it lies far out.
Very little of the supraoccipital is visible from behind, the inter- parietal terminating only a short distance above the foramen magnum.