360. Bulletin American Museum of Natural History. [Vol. XXXIV,, 
Meniscotherium tapiacitis Cope, 1882. 
Proc. Am. Phil. Soc., XX, 1882, p. 470; 1885, Tert. Vert., p. 506, pl. xxv, fig. 15. 
Type, No. 4425, fragmentary lower jaws with ps-mer. and p3 and msl; 
Fig. 17. Meniscotherium tapiacitis, lower 
from the Wasatch of the San Juan 
basin, “Alto la Zerta’”, N. Mex. 
D. Baldwin Coll’r. 
Distinctive characters: m3 = 
17 mm. (est.); lower molars with 
metastylid slightly developed on 
jaw, crown view. Type specimen. mg, absent on other molars. 
This diminutive species is repre- 
sented by the type only, and there are no specimens in the collection, 
except the one described below, which are intermediate in size between it 
and the type of M. chamense. 
Meniscotherium(?) priscum sp. nov. 
ype, No. 16145, a lower jaw fragment with dma—m left; from the Clark 
No. 16145 
Von Wee ee 
Fig, 18. Menisco- 
therium (?) priscum, 
fourth: milk molar 
and first true molar, 
crown and _ internal 
views. Type, Clark 
Fork beds, Clark Fork 
basin, Wyoming. 
Fork beds, Head of Big Sand Coulee, Clark Fork basin, 
Wyo. Exp. 19tt. 
Distinctive characters: diam; = 11.8 mm., m, ant. 
post. = 9.5 mm. tr. = 4.5 mm.; prominent metastylid 
on first molar. | | 
There are no characters in the two teeth present in 
this specimen to exclude it from the genus Meniscothe- 
rvum but it would not be surprising, considering the 
low horizon from which it comes, if more complete 
material forced the establishment of a new genus. It 
is true that Phenacodus and Ectocion both run through 
the same vertical range with very little change, but 
Menascotherium is a much more specialized form than 
either of these. 
The present species is slightly larger than M. tapiacitis and differs from 
it in having the well developed metastylid; from the larger forms it is 
readily separable by size. 
