PLIOHIPPUS. 



140 



F. V. Hayden, Geologist to the Expedition," Proc. Acad. Nat. Sci. Pliila. Vol. X, 1S58, p. 27, no figure. "The Extinct Mammalian 

 Fauna, of Dakota and Nebraska," Jour. Acad. Nat. Sci. Phila. (2) Vol. VII, 1809, pp. 299-302, PL xvii, type, figs. 10-13, paratype, 

 figs. 8, 9. 



Horizon and locality. — Niobrara River, near Fort Niobrara, Nebraska, Upper Miocene. Type collected by F. V. 

 Hayden, 1857. 



Type. — U. S. Nat. Mus. 569. (Leidy, 1858) "It is indicated in the Niobrara collection, by a specimen previously 

 noticed, consisting of a fragment of the upper jaw, containing the second and third temporary molars and their perma- 



3 



Fig. 118. Type and cotype of Pliohippus supremus Leidy, Acad. Nat. Sci. Phila. Coll., (Upper) Original figures 

 after Leidy, 1869, PI. xxvii, figs, 3, 4. Of these Leidy's description (p. 32S) applies to fig. 4; hence Gidley selected this 

 as the type. The cotype, fig. 3, belongs to another individual. 



(Left lower) Drawings of the type from cast Amer. Mus. 10776, (1 ) crown, (a) external, and (b) anterior views. (Right 

 lower) Drawings of cotype from east Amer. Mus. 10777, (1 ) crown, (a) external, and (b) anterior views. All figures natural 

 size. 



nent successors." (Gidley, 1907, p. 883) "A fragment of the right maxillary containing the posterior two milk molars, 

 and the first true molar partially calcified." Measurements: (Gidley, 1907, p. S83) dp 3 a.p. .024 tr. .021; dp 4 a.p. .020, 

 tr. .021; m 1 a.p. .025, tr. .022. 



Referred. U. S. Nat. Mus. 580 (Leidy, 1858) " Another specimen, in the same collection, belonging apparently to 



