78 SINCLAIR— ADDITIONS TO FAUNA OF [April 24, 



less abundant. Perhaps the new horned artiodactyl, Drepanomeryx, 

 presenting- a type of horn-core not hitherto known in North Amer- 

 ica, and a mastodon apparently allied to Mastodon americanus, may 

 be regarded as belonging to this category. The conception of old 

 and new faunal elements should not be unduly emphasized, because, 

 as our exploration of the Snake Creek beds plainly shows, we do 

 not yet know the extreme upward range in time of a number of 

 Upper Miocene genera and can merely say of the new, supposedly 

 Pliocene, forms that this is their first appearance. A suggestion 

 regarding climatic conditions may be found in the presence of croco- 

 diles and huge land tortoises, the latter rivalling in size those of the 

 Galapagos Islands, indicating, perhaps, that the approaching chill 

 of glacial times had not yet exterminated these cold-blooded types. 



DESCRIPTIONS OF NEW GENERA AND SPECIES. 

 Aelurodon sp. compare wheelerianus ? 

 The left ramus of a lower jar with p^ and m^ and alveoli for 

 the remaining teeth (No. 12068 Princeton University Geological 

 Museum, collecting locality lOooC) is referable to an Aelurodon of 

 about the size of A. zvheelerianus, from the type of which it differs 

 in the greater length of P4-my , the shorter jaw and the closer crowd- 

 ing of the premolars. It is either too small or too large to be re- 

 ferred definitely to any of the described species of Aelurodon, but 

 is hardly complete enough to be made a new specific type. 



Fig. I. Aelurodon sp., compare wheelerianus?, left ramus, side view. No. 

 12068, two thirds natural size. 



PAmphicyon sp. indesc. 

 A huge canid, possibly an undescribed species of Amphicyon, 

 is represented in the Princeton Snake Creek collection by the right 



