1905.] PRIMITIVE REPTILE PROCOLOPHON. 227 



There are many differences from the types of Procolo-phon in 

 other pai'ts of the skeleton, which suggest that the Fernrocks 

 specimens may belong to a different genus ; and there are 

 certainly two species from Fernrocks. 



Text-fig. 36. 



Outline showing the wedge-shaped snout of ProcolojjJwH spheHorhinus, 

 from Fernrocks. 



Pelvis. — The form of the ilium is partly shown in the figure of 

 the Donnybrook skeleton. Dr. R. Broom has figured the pubes 

 and ischia (Rec. Alb. Mus. vol. i. pi. 1. fig. 5) from Fernrocks. 

 The evidence that those bones belong to Procolophon is supplied 

 by the proximal end of the femur, which shows substantially the 

 same charactei's as the specimen fi-om Donnybrook, figured in the 

 Phil. Trans. Royal Soc. in 1889. It is associated with dorsal 

 vertebrae with small intercentra and a median longitudinal groove 

 on the ventral aspect ; with caudal vertebrae rovinded on the ventral 

 aspect carrying ribs which extend transversely beyond the ischia. 

 The ilia are less cleai-ly seen than in the original slab. The chief 

 characters of this pelvis are the foramen perforating the pubis, 

 the antero-posterior extension of the crest of the ilium, and the 

 expanded forms of the short pubes and longer ischia. In form 

 these ventral bones of the pelvic basin differ from Theriodonts 

 like Cynognathus in the absence of an obturator foramen, though 

 there is a small semicircular notch on the anterior border of a right 

 ischium. The peiforation of the pubic bone is a character of 

 Pareiasaurus and of other large undescribed genera in which I 

 have seen the bone in the South- African veldt. It also occurs 

 in Phocosanrus and Titanosuchths. The character is not seen 

 in Microgomphodon^ in which the ischium is similar in form. 



