28 ON THE EXTINCT MAMMALIA OF 



CARNIVORA. 



Of Carnivora there are fifteen extinct species, exclusive of Insectivora, described in 

 the succeeding pages and referred to seven genera, of which all except one are 

 extinct, and of which three are for the first time noticed. 



Four species of the genus Canis, together with a supposed feline animal named 

 ^lurodon ferox, and a feline animal of the genus Pseadcelurus, belong to the pliocene 

 tertiary formation of the Niobrara River. I am, however, not positive that the 

 remains described under the names of Canis scevus, C. temeiririus and C. vafer are all 

 really pliocene fossils; it is not improbable that some of them may have belonged to 

 varieties of more recent or even of existing Wolves. 



Another extinct carnivore, apparently allied to the Coaiis, and named Leptarctus 

 primus, is indicated by an isolated tooth, found in a formation, also viewed as of the 

 pliocene age, at Bijou Hill, east of the Mississippi River, about ten miles below the 

 mouth of White River. 



The remaining animals consist of three species o^ Hycenodon, ivfo oi Amiiliicyon, 

 two 0? Drepanodon, and a genus of peculiar character allied to the latter, and named 

 Dinictis. The remains of these were discovered in the silico-calcareous rock of the 

 miocene bed B, of Dr. Hayden's section, in association with remains of Oreodon, 

 Turtles, &c., in the Mauvaises Terres of White River, Dakota. 



GANID^. 

 CANIS. 



Canis s^vus. 



An extinct species of Wolf, probably a near relative, if not the progenitor of the 

 existing American Wolf, Canis occidentalis, is supposed to be indicated by two 

 mutilated fossil fragments of lower jaws, obtained by Dr. Hayden from the sands of 

 the Niobrara River. 



Both specimens belonged to old animals. The best preserved one, represented in 

 figure 9, plate I, retains the sectorial molar and the succeeding tubercular molar; 

 the other specimen retains the latter tooth and the third premolar. 



The fragments accord in form, proportions and size with the corresponding portion 

 of the lower jaw of large varieties of the Canis occidentalis. 



The measurements of the two specimens, in comparison with those of a large 

 variety of the Canis occidentalis from Oregon, are as follows : 



