ProtoMppus, PlioMppus, Hippidion. 
786 
4883. t? avus, Marsh, Amer. Journ. Sc., VII, 
1874, p. 253. 
■fMiocaen. sup. 
Oregon. 
4884. t placidus, Leidy, Ext. Mam. Fauna, 1869, 
p. 277, pl. 17, 18; Ext. Vert. Fauna, 1873, 
p. 249, pl. 20; Cope, BulI.Geol.Surv. 1873 
(1874), p.l4 (exclus. pedibus); Amer. Nat., 
1892, p. 942, pl. 24; Anu. Rcp. Texas 
1892 (1893), p. 26, 34, pl. 11, lig. 3—8. 
grahiin, Leidy (Hipparion). 1. c., p. 287, 
pl. 18; Cope, Proc. Amer. Phil. Soc., 1889, 
p. 446, lig. 16, 17 (exclus. synon.). 
a. — panulus, Marsh, Amer. Journ. Sc., 
XLVI, 1868, p. 374; VII, 1874, p. 251; 
Cope, Ann. Rep. 1892 (1893), p. 25, 29, 
pl. 11, fig. 1, 2 (Vide: sp. 4859). 
fMiocaen. super, 
Colorado, Nebraska, 
Texas. 
Nebraska. 
-j-Miocaen. sup. 
Nebraska, Texas. 
969. tPliollippus, Marsh, 1874. 
4885. t pernix, Marsh, Amer. Journ. Sc., ATI, 
1874, p. 262. 
fPliocaen. America 
sept., Nebraska. 
4886. t robustus, Marsh, Amer. Jouru. Sc., VII, fPliocaen. Nebraska. 
1874, p.253. 
970. t Hippidion, Owen, 1870. 
Equu.% p., Lund, Rhinippus et Hippidmm, Burm., Onohippidium, Moreno. 
4887.f neogaeum, Lund, Dansk. Vid. Selsk., XU, 
1 846, p. 90, pl. 49 ; Owen, Phil. Trans., 
1869 (1870), p. 560; Burm., Caball. Fosil. 
Pampa, 1875, p. 65 ; Suppleim, 1 889 ; Descr. 
Phys., 1879, p. 479; Ameghino, Mam. 
Fosil, 1889, p. 615, pl. 28. 
Devillei, Gerv., Voy. Castelnau, 185.5, 
pl 7, fig. 11, 12 (nec Burm.). 
fPliocaen. sup. 
America merid., 
Brasil merid., 
Argentina, 
Boli via. 
4888. f principale, Vmnd, Dansk. Vid. Selsk., XII, 
1846, p. 90, pl. 49; Burm., Caball Fosil. 
Pampa, 187.5, p. 66, pl 3; Suppi 1889, 
pl. 11; Amegh., Mam. Fosil, 1889, p. 616, 
pl 27, 28. 
fPliocaen. sup. 
America merid., 
Brasil merid., 
Argentina, Uruguay. 
