46 BULLETIN 53, UNITED STATES NATIONAL MUSEUM. 



4944. Megacerops dispar (Marsh). See Brontops validus. 



154. Megalomeryx niobrarensis Leidy. Cotypes. 



155. Teeth. Loup Fork (Miocene). Niobrara River, Nebraska. 



Leidy, Proc. Acad. Nat. Sci. Phila., 1858, p. 24; Journ. Acad. Nat. 

 Sci. Phila. (2), VII, 1869, pp. 161, 382, pi. 14, figs. 12, 13. 



= Camelops kansanus. 



See Procamelus ? niobrarensis. 



830. Megatherium mirabile Leidy. Cotypes. 



832. Anterior part of jaw, posterior part of cranium, and astraga- 



837. lus. Pleistocene. Skiddaway Island, Georgia. 



Leidy, Proc. Acad. Nat. Sci. Phila., VI, 1852, p. 117; Smithsonian 

 Contrib. to Knowl., VII, Art. V, J 855, p. 49, pi. 15. 



2131. Menacodon rarus Marsh. Type. 



Left ramus of jaw with four premolars and three molars. 

 Morrison (Jurassic). W3^oming. 



Marsh, Amer. Journ. Sci. (3), XXXIII, 1887, p. 340, pi. 10, fig. 5. 



2885. Meniscoessus ccelatus (Marsh). See Tripriodon ccelatus. 



1093. Meniscotherium chamense Cope. Type. 



Part of upper right maxillary containing one broken pre- 

 molar (p 4 ), and three molars (m-m 3 ). Eocene. New 

 Mexico. 



Cope, App. FF 3 Ann. Rept. Chief Engineers, in Rept. Sect'y. War, 

 II, Pt. II, 1874, p. 596; Rept. U. S. Geogr. Surv. W. 100th Merid., 

 IV, Pt. II, 1877, p. 252, pi. 66, fig. 18. 



4249. Menops varians Marsh. Paratype. 



Skull. Lower beds, White River (Oligocene). Bad Lands, 

 between Che) T enne and White rivers, South Dakota. 



Marsh, Amer. Journ. Sci. (3), XXXIV, 1887, p. 329, text fig. 10. 



= Brontotherium leidyi. 



2572. Merychippus calamarium (Cope). See Hippotherium cala- 

 marium. 



578. Merychippus insignis Leidy. Plesiotypes. 



583. (1) Two upper molars, m 2 and m 3 , of right side; (2) frag- 



ment of maxillary of right side containing six teeth, 

 p 2 -m 3 . Loup Fork (Upper Miocene). Niobrara River, 

 Nebraska. 



Leidy, Journ. Acad. Nat. Sci. Phila. (2), VII, 1869, p. 296, (1) pi. 18, 

 figs. 49, 50; (2) pi. 17, fig. 5. 



569. Merychippus mirabilis Leidy. Type. 



Upper milk molars (dp 3 , dp 4 ) and first molar (m 1 )- Loup 

 Fork (Upper Miocene). Niobrara River, Nebraska. 



Leidy, Proc. Acad. Nat. Sci. Phila., 1858, p. 27; Journ. Acad. Nat. 

 Sci. Phila. (2), VII, 1869, p. 299, pi. 17, figs. 10-13. 



= Protohippus mirabilis. 



