206 



OSBORN: OLIGOCENE, MIOCENE, PLIOCENE EQTJIDJ3. 



scapula) and the pelvis." Measurements: (Scott, 1894) superior molar-premolar series .147; superior premolar series 

 .083; inferior premolar-molar series .148. 



Type figure. — Text Fig. 167 of this Memoir. 



Characters. — (Scott, Trans. Am. Philos. Soc. 1894, pp. 94, 95) "From the best-known European species, A. aureli- 

 anense, it differs in the following respects; (1) Larger size of the teeth in proportion to the skeleton; (2) absence of 

 enamel invaginations in the lower incisors; (3) smaller size of the antero-external buttress on p 2 ; (4) the transverse crests 



Fig. 168. (4) Skull of the type of Hypohippus osborni Gidley, Amer. Mus. 9407. One-half natural size. (2) Superior 

 molars of H. osborni Gidley, Amer. Mus. 9395, a referred specimen. Natural size. 



of the upper molars and premolars are less sinuous; (5) po has the anterior half of the crown flattened on the outside and 

 no external valley; (6) the diastema between the lower canine and px is relatively shorter and the symphysis is much 

 narrower; (7) the proximal end of the humerus differs in details that will be explained in the full description; (8) the median 

 digit is more enlarged and its ungual phalanx shorter and more rounded, but also flatter and more depressed." 



