42 BULLETIN 53, UNITED STATES NATIONAL MUSEUM. 



573. Hypohippus affinis (Leidy). Type. 



Leidy, Journ. Acad. Nat. Sci. Phila. (2), VII, 1869, pp. 311,402, 

 pi. 21, figs. 11, 12. 



See Anchitherium (Hypohippus) affinis. 



1 10. Hyrachyus agrarius Leidy. Type. 



Left ramus of jaw without teeth. Bridger (Eocene). 

 Smiths Fork, Green River, Wyoming. 



Leidy, Prel. Rept. Geol. Surv. Wyoming, etc., 1871, p. 357; Rept. 

 U. S. Geol. Surv. Terr., I, 1873, pp. 60, 327, pi. 2, fig. 11. 



660. Hyrachyus agrarius Leidy. Plesiotype. 



Leidy, Rept. U. S. Geol. Surv. Terr., I, 1873, pp. 60, 327, pi. 2, fig. 12 

 (originally described as H. agrestis). 



See Hyrachyus agrestis. 



660. Hyrachyus agrestis Leidy. Type. 



Portion of left lower jaw containing three teeth, dp.,, dp 4 , 

 m x . Bridger (Eocene). Blacks Fork, Green River, 

 Wyoming. 



Leidy, Prel. Rept. Geol. Surv. Wyoming, etc., 1871, p. 357. 



= Hyrachjms agrarius. 



661. Hyrachyus modestus (Leidy). Type. 



Leidy, Rept. U. S. Geol. Surv. Terr., I, 1873, p. 67, pi. 2, fig. 13. 

 See Lophiodon modestus. 



1 106. Hyrachyus singularis Cope. Type. 



Right maxillary bone containing two premolars (p 3 , p 4 ), 

 and three molars (rr^-m 3 ), associated with part of max- 

 illary of opposite side containing p^-m 3 . Wind River 

 (Eocene). New Mexico. 



Cope, Syst. Cat. Vert. Eocene New Mexico, 1875, p. 19; Rept. U. S. 

 Geogr. Surv. W. 100th Merid., IV, Pt. II, 1877, p. 267, pi. 66, 

 fig. 17. 



= Heptodon singularis. 



138. Hyracodon nebrascensis (Leidy). Type and paratype. 



x 39- Leidy, Proc. Acad. Nat. Sci. Phila., 1856, p. 92. 



See Rhinocerous nebrascensis and Aceratherium nebras- 

 censis. 



1079. Hyracotherium angustidens (Cope). Type. 



Cope, Rept. U. S. Geogr. Surv. W. 100th Merid., IV, Pt. II, 1877, 

 p. 265, pi. 66, figs. 3, 3a. 



= Eohippus angustidens. 

 See Orohippus angustidens. 



