306 Bulletin American Museum of Natural History. [Vol. XXXIV, 
arrangement and facets of the lunar and magnum. In the Yale specimen ~_ 
the centrale is preserved. The relative proportions of the metapodials in 
both fore and hind feet and the form of the phalanges, including the 
unguals, are similar to those in the Hyracops figures. The differences, 
indicated in the carpus of the latter, seem to be due to an error in recon- 
struction rather than to any actual differences in the specimens. I can see 
no reason for considering Hyracops as distinct from Menascotherium. 
Meniscotherium Cope, 1874. 
Syn. Hyracops Marsu, 1892. 
Type, M. chamense, from the Upper Wasatch of New Mexico. 
Both the geological and geographical distribution of this genus, and 
hence of the family, are unusual and interesting. In New Mexico it first 
appears in the Upper or Largo beds of the Wasatch and is one of the most 
abundant forms in this horizon, and serves as an excellent horizon marker. 
There is no trace of it from the Lower Wasatch horizon of that region,' - 
while from the underlying Torrejon and Puerco formations there is no form 
which might in any way be considered as belonging to this group. The 
only specimen of the genus which has been previously recorded from out- 
side of this rather restricted New. Mexican area is a single individual from 
the Lost Cabin beds of the Wind River basin, Wyoming, found in 1909.2 
Two others from the same horizon, one found in 1896, the other in 1909, 
~ have recently been discovered in the collection. These specimens while 
extending the geographical range of the genus considerably do not 
extend the geological range since the Lost Cabin is considered the equiva- 
lent, or nearly so, of the Largo beds. A fourth specimen from Wyoming, 
collected in 1911, does, however, extend the geological range. This is 
a lower Jaw fragment, with the fourth milk molar and first true molar, 
from the Clark Fork beds. While it represents a species distinct from the 
later forms of the Largo and Lost Cabin beds it cannot at present be excluded 
from the genus Meniscotherium, although the discovery of more complete 
remains may necessitate its removal. The interval between the Clark Fork 
and the Lost Cabin forms a considerable gap, represented by the Sand 
Coulee, Gray Bull and Lysite beds, totaling not less than 1300 feet of sedi- 
ment, in which this genus does not occur, and it is of interest to note in this 
1 Cope has stated that Meniscotherium is from the Lower Wasatch beds, but this is an 
error. 
2 W. Granger, Bull. A. M. N. H., X XXIII, 1914, p. 206, foot-note. 
