188!».] NATURAL SCIENCES OF PHILADELPHIA. 221 



transverse processes are slender and the pleurapophysial plates but 

 little developed. The hind part of the neural arch of the fourth is 

 broken away so that nothing can be determined as to the character 

 of the spine and the opisthapophyses ; the pleurapophysial plate is 

 much better developed than on the third vertebra. 



Fore-Limb. 



This member is but very scantily represented in the collections, the 

 only portions of it which I have seen being fragments of the humerus 

 and radius. Fortunately there can be no doubt as to the refer- 

 ence of these specimens, as they were found associated with a skull 

 i Nil 10,012 of the Princeton Museum). The humerus is too much 

 mutilated for description, further than to say that this bone is much 

 stouter than the femur would lead one to expect; the supinator ridge 

 is very prominent and runs far up the shaft. 



The radius is distinctly feline in character. The proximal end is 

 formed by a small disc-like head with a concave facet for the 

 capitellum of the humerus ; the concavity is not quite so deep and its 

 margin not so even as in the cats, being notched in the middle of the 

 front edge, which edge is thus given a sigmoid curve. The head 

 does not project inwardly beyond the line of the shaft, as is so 

 markedly the case in the lion. The articular surface for the ulna 

 forms a narrow band which extends around two-thirds of the cir- 

 cumference of the head, considerably more than in the lion and 

 indicating very complete powers of pronation and supination. 

 Distal to the head the shaft gradually contracts and becomes 

 irregularly oval in section. The lower part of the shaft is quite 

 broad, thickened on the outer side and tapering to a thin edge on 

 the inner ; the distal end is somewhat rugose and narrower than 

 the lower part of the shaft, the rugosities are much less prominent 

 than in the recent forms. The facet for the scapho-lunar is broad 

 towards the ulnar side and slightly concave in both directions, but 

 suddenly becomes much narrower internally. There is a small 

 facet on the external side for the distal end of the ulna. 



It is interesting to note that the distal end of the radius in the 

 Bridger creodont, Miacis bathygnathus, is very similar to that of 

 Dinietis, but the carpal surface is somewhat differently shaped, and 

 the styloid process less prominent. 



