306 Mr. D. M. S. Watson on 



Pelvic Girdle. 



The only new point of interest about the pelvic j^irdle is 

 tlie presence of a thickened l)ar across the pubes, so tliat the 

 symphysis is suddenly thickened as in Labidosaurus at one 

 point. 



Comparison ivitk V. brevirostris. 



The reptile whose structure has just been described differs 

 from that described by Willistou as Varanosaurus brevi- 

 roatris in a considerable number of characters. Willistou 

 lias already liste;l the skulUproportious aud the dentition. 

 To these we may add : — 



'^rbe holocephalous ribs. 



'I'he tlattcncd and expanded ribs in the pectoral region. 



Tbe hori:^out.dly placed zygapophysial articulatiiij;' surfaces 



and the rather heavier arches of the type species. 

 The presence of tvvo coracoidal elements in the type. 

 Tlie thickening of a part of the pubic symphysis. 

 The very probable presence of a complete ten)poral arcade 



in the type. 



Williston's animal is, in fact, a more specialized type, 

 quite worthy of generic rank. 



Comparison with Dimetrodon, 



With fuller knowledge, the skull of Vuranosaurus shows 

 many rather unexpected rescndjlunccs to that of Vimetrudun. 



Comparison of the figures in this paper with tliose given 

 hy Case, Broom, and especially fig. 44 of v. Huene's recent 

 l)aper * will show at once great resemblances in the back of 

 the skull and the relations of the interparietal and tabularcs, 

 and particularly the relation of the suprateniporal to the 

 parietal, tabular, and squamosal. 



The structure of liie back of the lower jaw is also very 

 similar in the two types. 



In fact, there can be no doubt that JJroili was pcrfvcily 

 correct in his oiiginal idea that Varanosaurus is a I'clyco-' 

 saur ; there i.s also no doubt that it is a |)rimitivc memi)cr of 

 that group, in a paper now in the jjrcss 1 have siiown, 

 following JJroom, that the Pelycosaurs are truly members of 

 the same great group as the South-African Tiierapsids, 

 differing only in the more [)rimitive features of the limbs 



* Jiiill. A'lior. Mus. Nat. Hist. vol. xxxii. ait, xviii, p. -jTi'd, 



