300 
EODENTIA. 
jaws are nearly or quite equal; in the S. pansus, the first of both series is 
conspicuously the largest. The second and third present a difference in 
proportions in S. nebrascensis, while they are equal in the S. pansus. In 
the same way, the transition in size from the third to the fourth is abrupt 
in 8. nebrascensis and very slight in 8 . pansus. The superior molars are rep¬ 
resented as more quadrate in the 8. nebrascensis, and there are two fossettes 
behind the external inflection. This cannot be due to attrition alone, as they 
are related antero-posteriorly, and are therefore not divisions of a single 
transverse fossette. As compared with the 8. pansus, the 8. viciacensis has a 
still smaller posterior upper molar, which often lacks the internal enamel 
inflection; and the fossettes are one more in each crown, as in 8. nebrascen- 
sis.* The enamel inflections of the inferior molars are said to be opposed, 
and not alternating, as in both the American species. 
The 8teneofiber pansus was about as large as Prairie Dog {Cynomys 
Judovicianus'), but more robust, 
EUMYS, Cope. 
Cope, Ann. Eept. U. S. Geol. Surv. Terrs., 1873, (1874), p. 474.—Leidy, Ext. Mamm. 
Fauna Dak. and Nebr., 1869, p. 342 (name only). 
The characters of this genus as pointed out in the article above cited 
cannot be verified on the species below described, as the mandibular ramus 
with dentition is the only part preserved. The characters of the molar 
teeth are identical in character wflth those of the Eumys elegans, and it is 
therefore provisionally referred to the same genus. They also resemble 
those of the genus Hesperomys-, to which I originally referred it. 
Eumys loxodon, Cope. 
Plate Ixix, fig. 15. 
Hesperomys loxodon, Cope, Proc. Acad., Phila., 1874, 150; Ann. Eept. Chief of Engi¬ 
neers, 1874, ii, 605. 
Eumys loxodon, loc. cit., 1875, p. 993. 
A nearly entire mandibular ramus, with all the teeth preserved, was 
found in the same deposits as the preceding species. Molars subequal, 
* This species is stated by Leidy, on the authority of Hayden, to have been derived 
from the White Eiver Miocene; it will be necessary to verify this statement, as the 
IS. 2 mHSUS is a Loup Fork species. 
