23-— ox THE CLASSIFICATION OF THE THEKIODOXTS 



AND THEIR ALLIES. 



Bv K. Bkoom, M.D., B.Sc, C.M.Z.S. 



The first attempted classification of the S. African Triassic 

 reptiles was that given bv Owen in his PalceoiUnlug). In the Order 

 Anomodontia he placed three " families "' or sub-orders Dicynodon- 

 tia, Crj'ptodontia. and Cvnodontia. The types of these grouj^s were 

 respectivelv Dicvnodon. ()udehodon, and (lalesaurus. 



Huxley in 1871 modified Owen's arrangemeiU b\ placing 

 Oudenoden with Dicynodon in the order Dicynodontia. 



When in 1876 Owen published his Catalogue of the Fossil 

 Reptilia of -South Africa a large number of new forms had been dis- 

 covered and much more was known of the details of structure. It 

 was therefore possible for him to give a more satisfactory classifica- 

 tion than that which had previously been advanced. Galesaurus, 

 Cynochampsa, and a number of other allied genera were umted 

 together to form the Order Theriodontia, and the Order Anomodontia 

 was retained for Dicvnodon. Oudenodon. and a few other allied 

 genera. It seems fairly evident that Owen all along regarded 

 DiCynodon as the ty])ical genus of the .AiKinnMlontia and that he 

 considered he had made a mistake by including in his early classifica- 

 tion Galesaurus with the Dicvnodonts as (me nf ihe Anomodontia. 



Between 1876 and 1888 comparativeK Utile work was done 

 among the S. African forms, but many new types were discovered in 

 the Permian rocks of X. America, and described l)y Cope. These 

 American forms beliMig to at least two well-marked groups. The first 

 comprises a few genera, which in rlentition resemble somewhat the 

 S. African Theriodonts. but which are now known to differ consider- 

 ably from the African tvpes in manv imj)ortant )Hjints. For these 

 (Clepsydrops, Dimetrodon. etc.) Co])e founded the Order Pelyco- 

 sauria. The reptiles of the other group are characterised by having 

 the temporal fossa roofed. These Cope was at first inclined to ])lace 

 in the Pelvcosauria, but he afterwards founded a new order for their 

 reception — the Coivlosauria. Cnfortunalelv he chose as the tvpe 

 of the Cotvlosauria the genus P^mpedias which is very imperfectly 

 known. Some of the other .-Vmerican genera (Pariotichus. Pantylus, 

 etc.) seem to agree fairlv closelv with the S. .\frican Pareiasaurus, 

 but it is a little doubtful whether Fmpedias does. Owing to this 

 doubt it is probably advisable at present to make use of Seele\'s 

 name Pareiasauria for those primitive reptiles wnth the temporal 

 region roofed .somewhat after the manner of the Labvrinthodonts. 



Cope proposed in 1878 to form a large grou]) the Theromorpha 

 — for these re])tiles exhibiting mammal-like characters, and sub- 

 divided the group into the orders or sub-orders .\nomodontia and 

 Pelycosauria — the Anomodontia comprising the Dicynodonts, and 

 the Pelvcosauria the S. African Theriodonts as well as the American 



