DAKOTA AND NEBRASKA. 177 



depth, which exceeds that in the Hog. Its fore part, however, beneath the position 

 of the orbit, is as remarkably narrow compared with its condition in a similar position 

 in relation to the orbit in the Hog. This comparative weakness of the connection of 

 the zygoma with the side of the face is duly compensated for in the additional abut- 

 ment to the zygoma, in the strong post-orbital arch. The outer surface of the 

 zygoma, rather less vertical posteriorly than in the Hog, at its anterior part slopes 

 from the orbital margin downward, outward and backward. 



The posterior root of the zygoma, in association with the mastoid and paramastoid, 

 forms a comparatively high, wide and deep arch, communicating at its inner part 

 with the orifice of the external auditory meatus. The anterior surf\ice of the arch is 

 a broad deep slope contributing to the temporal fossa. 



The entrance of the orbit is more advanced in position than in the Hog, and holds 

 nearly the same relative position as in the Hippopotamus, but is not elevated as in 

 the latter, being below the level of the forehead as in Chonrodes, the Hog and the 

 Peccary. Its ant-orbital margin is on a line with the second true molar tooth. It is 

 entire, as in ruminants and ordinary solipeds, and as is also rarely the case in the 

 Hippopotamus. Posteriorly it is formed by a strong arch, to which the frontal and 

 malar contribute nearly equally. It is vertically ovoid, with the narrower part 

 above; and it is larger than in the Hog, and rather more directed forward. 



The orbital cavity has a more forward and less upward direction than in the Hog. 

 It is directed obliquely forward, comparatively slightly upward, and approaching the 

 entrance is rather more abruptly directed outward. 



The supra-orbital margin is prominent, and at its fore part everted. The ant- 

 orbital margin presents a strong median, mammillary eminence of the lachrymal 

 bone, defined above and below by notches. 



The lachrymal orifice is single, longitudinally oval, and is situated within the orbit 

 internal in position to the lower of the notches just mentioned. 



The face is long and cylindroid as in the Hippopotamus, but is not encroached upon 

 by bony excrescences of the canine alveoli, as exist in the latter and other suilline 

 animals. In the corresponding position the face presents the convex swell of the 

 canine alveoli as observed in ordinary carnivora, like the Lion and Bear. 



The premaxillary projects forward nearly as much as in the Hog. Its lateral 

 surflxce is more convex both fore and aft and from above downward. 



The facial surface of the lachrymal is large and square, and contributes to the 

 general slope from the forehead and ant-orbital margin to the side of the face. There 

 is no disposition to the formation of an ant-orbital fossa or depression such as exists 

 in the Hog and Peccary. 



The infra-orbital foramen is as large as in the Hog, and is situated above the 

 position of the third premolar tooth. In an old adult specimen there exists a second 



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