308 | Bulletin American Museum of Natural History. | [Vol. XXXIV, 
Key to Species of Meniscotherium (measurements from types). 
A. Strong metastylid on all three lower molars. 
Cece eee Ue ee ce ec re ea ee ha eh M. chamense. 
Ob Oe ee 20M i oy ca es IM chamense terrerubre. 
B. Metastylid weak on m;, absent on anterior molars. - 
ee ee eeu eee re ee ee a eee ak M. tapiacitise 
Meniscotherium chamense, Cope 1874. 
Report Vert. Fossils N. Mex. p. 8; 1877, Ext. Vert. N. Mex., p. 262; pli. ixvi, 
fig. 18. 
Type, Coll. U.S. Nat. Mus., No. 1093, a fragment of right maxilla with 
the three molars; from the San Juan basin, N. Mex. E. D. Cope, 1874. 
Distinctive Characters. m'* = 21 mm. Metastylids prominent on all 
three lower molars. 
The type is the only specimen of this genus secured by Cope during his 
exploration of the New Mexican Wasatch in 1874. Subsequently his col- 
lector, David Baldwin, obtained remains of a large number of individuals, 
including nearly all parts of the skeleton. There is but very little associa- 
tion of parts in these specimens and they represent individuals of various 
ages and show a wide range in size. 
A smaller form is represented by a single specimen, the type of M. 
tapracitis, while of the larger species 
there are over fifty specimens of 
portions of skulls, mandibles and 
jaw fragments. Of these latter the 
} types of M. chamense and M. terre- 
ase os rubre represent the small and large 
a extremes and the remaining speci- 
mens are all intermediate in size, 
the majority being closer to M. 
. terrerubre. 
Fig. 16. Meniscotherium chamense, upper I refer as belonging to M. cha- 
ei lower teeth, crown views. 'Topotype. — MeNSE Nos. 16254, 162 ave 4438, 4440, 
all fragments of maxilla from the 
type locality. Of these No. 15257 approaches the type most closely 
(M'? = 22 mm.) and, since it presents both upper and lower teeth, forms 
a very good topotype (Fig. 16). 
From the Lost Cabin beds of Muddy Creek, Wind River basin, Wyo., 
there is a-specimen of Meniscotherium found by the Expedition of 1909 
