1902.] Matthew, A Skull of Dinocyon from Texas. I3' 



of Mr. J. W. Gidley, the discoverer of many of the choicest 

 specimens of fossil mammals in the collections of the Ameri- 

 can Museum and of Princeton University. 



Dinocyon (?Borophagus) gidleyi, sp. nov. 



Generic and Siibfainily Characters. — 'Denixtion, 3.i±i_ Premolars 

 _ ' -' ' 2.1. ? 4.3 



much reduced, without posterior accessory cusps, one or two of the 

 inferior series perhaps absent. Camassials small and low with re- 

 duced shear, tubercular teeth very large with low cusps. Jaw very 

 deep and massive, facial part of skull elongated, sagittal and occipital 

 crests high, brain-case small. BuUas inflated, but smaller than in 

 typical Canidas, mastoid process small, paroccipital process moderately 

 long, coossified with the bulla. (In the bears the mastoid process is 

 much enlarged, the paroccipital reduced, and the tympanic bulla not 

 inflated.) 



Subgencric Characters. — Teeth like those of Amphicyon in form, 

 especially such species as .4. americanus Wortman. Upper molars 

 much wider transversely, and the first more trigonal in outline than 

 in Dinocyon tlienardi. 



Specific Characters. — Size somewhat greater than in D. thenardi or 

 D. {" Aelurodon") niceandrinus , premolars more reduced and pre- 

 molar region of the jaw longer than in the latter species or in Boro- 

 phagus diversidens. 



It is difficult to place this fine species in any of the de- 

 scribed genera. In form and character the carnassials and 

 molars (Fig. 2) are like pa. 



those of Amphicyon . | ^^^— ^"^li^^^'" pa. 



But the third upper /^ ^S^^:'-"^^ 



molar, a well developed /^'^,' \ .^ ■^■''' V^^flli^Ojl 

 tooth in Amphicyon, is ^'^'^ y' pr.-,\1^^ai W^jf 



absent from either side \ W '^ 7 



of the Texas skull, as it '"' ^'^ 



is in Dinocyon and Hemi- Fig. 2. Grown view of Teeth x i. 



cyon, and probably in 



Pseudainpliicyoji.' The size is near that of D. thenardi, with 

 which the proportions of the lower teeth, so far as they can 

 be seen, agree fairly well. But the first and to some extent 

 the second upper molars, are trigonal and much extended 

 transversely, while in Dinocyon, and still more in Heniicyon, 



' Schlosser, /. c. 



