EUNOTOSAUKUS AFRICANTJS PflOM BEATTFORT WEST. 585 



away from the bone beneath in places, but there is no proof that it 

 is a separate ossification. Some approach to this type of rib is seen 

 in Cratceomus from the Gosan Beds.^ Still, as the centrums have a 

 Chelonian aspect, it is interesting that the ribs should also simulate 

 the ribs and costal plates of Chelonians. But they were clearly free 

 at their margins, and rather resembled the ribs of certain Edentata, 

 like Oyclothurus, in their superior aspect. The ribs are about 5 

 centimetres long. There are one or two wide thin bones in the ven- 

 tral cavity which have the aspect of being sternal ribs, or their 

 representatives. And although there is no proof that they are 

 correctly identified, the possibility of such ossifications being present 

 is worth recording, as it might be a further approximation towards 

 the Chelonian type. Nevertheless, too much importance may be 

 attributed to such characters, unless it is remembered that the 

 specimen affords no proof that the whole of the dorsal vertebras are 



At the posterior ventral extremity is the left os pubis (see fig. 1), 

 a flattened bone of moderate size, thin, rather longer than wide, 

 with a notch at the external posterior border, which recalls the con- 

 dition of the bone in various Mesosauria. At the right hinder corner 

 of the specimen are fragments of two parallel slender cylindroid 

 bones which may be parts of the tibia and fibula. 



From the fragmentary condition of the remains, it seems to me 

 inexpedient to determine absolutely the systematic position of the 

 genus. Every character preserved differs from those of South 

 African fossils hitherto known, with the exception of the imperfect 

 pubis. This bone strongly suggests that the specimen is referable 

 to the Mesosauria, in which it is likely to be placed, in a division 

 distinct from the Proganosauria. 



In conclusion I would express my thanks to the Committee of the 

 Government Grant Fund of the Eoyal Society, for assistance in 

 making this investigation. 



^ Quart. Journ. Geol. Soc. vol. xxxvii. (1881) pi. xxvii. fig. 18. 



