18*79.] NATURAL SCIENCES OF PHILADELPHIA. 185 



Bernard, the bulldog, greyhound, and other races, nor in any of 

 the feral or extinct species of the genus examined. It appears to 

 be associated with an increased size of the brain, and to bean 

 adaptation to the vermis of the cerebellum. The expansion of 

 the brain is also indicated by the protuberance of the frontal re- 

 gion, and the wide separation of the temporal fossae by a smooth 

 space on each side of. the sagittal suture. This space does not 

 exist in the greyhound, but a narrow one is found in the bulldog. 

 These characters are important on various grounds, but are here 

 mentioned in reference to the species of Synagodus and Dysodus, 

 where they reappear. The absence of the second inferior tuber- 

 cular molar is also not uncommon in the " black and tan" terrier. 

 I do not see the propriety of retaining the generic name Nycte- 

 reutes, Terara. for the Canis procyoninus of Japan. The pecu- 

 liarity it presents in the form of the first superior tubercular 

 molar, the only one 1 on which the genus reposes, I would regard 

 as specific only. 



Vulpes. 



I would, with Gill, refer to this genus the species mentioned 

 by Gray and others under the generic names Pseudalopex, Fenn- 

 ecus, and Leucocyon. The form of the post frontal process cer- 

 tainly does not furnish generic characters. 



TJrocyon, Baird. 



The peculiar cranial ridges, in which this genus resembles one 

 of the extinct genera of Ilustelidse, appears to me to be the cha- 

 racter which warrants its separation from Vulpes. 



Enhydrocyon, Cope, Bulletin U. S. Geological Survey, Terrs, v, 56, 1879. 



Two species from the White River beds of Oregon are known. 



Tomarctus, Cope, Ann. Report U. S. Geol. Surv. Terrs. 1873 (74), p. 519. Paleon- 

 tologieal Bulletin, 1873, Aug. 20, 1873. 



One species known from the Loup Fork beds of Colorado. It 

 is uncertain whether this genus has two orthree premolars. Should 

 it have three it must be compared with the Brachycyon of Filhol. 

 But the inferior sectorial tooth of that genus is as yet unknown. 

 Speothus, Lund, 1843. Cuon, Hodgs. 



One extinct species of this genus was found by Lund in caves 

 in Brazil. Another species, Speothus primeevus, is now living in 



1 According to the figures of Temminck and Schlegel. 

 13 



