304 Bulletin American Museum of Natural History. [Vol. XXXIV, 
A single specimen from the lowest beds represents a.species considerably 
smaller than E. ralstonensis and, hence, the smallest of the genus. In the 
absence of all teeth but the lower molars the measurements must suffice for 
specific characters. The first and second molars are much worn. but they 
seem to show rather less crowding inward of the hypoconulids than in the 
other species. The jaw is much checked but indicates a relatively deeper 
ramus than in EL. ralstonensis. 
Distribution of Lower Eocene Species of Phenacodontide. 
Wyoming | N. Mex. 
Bighorn & Wind River Basins | Evanston | San Juan Basin 
3 ee eee | 
Q eaag | ) 
se et ee 
Bd ye ee Peete: |B 
aa me | Oo op o hd — | < 
PRICES fe Ditahcc tyes h iescs SeeP a Sa 6 ED ae ea a ay coe | Pee es 
Phenacodus | 
P. primevus x x a x ges 
P. primzevus robustus | x | 
P. primzvus hemiconus | X x res 
P. intermedius ? x < x mae: 
P. copei | ee poe ase 
P. vortmani a ? ? Bae 
P. brachypternus | x 3h Gea: ae ce 
P. astutus | Lame 
Ectocion | 
E. osbornianus x x x 
E. superstes — | x ? 
E. ralstonensis | | » ~ x 
KE. parvus | : , x 
X indicates horizon and locality of type. 
Family MENISCOTHERIIDA Cope, 1882. 
‘This family of condylarths was established by Cope to include the single 
genus Menascothertum with skeleton characters more or less like those of 
the Phenacodontide, but with teeth much too highly specialized to allow 
of its being included in that family. Meniscotherium was described by Cope 
‘This is the typical Lost Cabin of the Wind River basin; no Phenacodonts have been 
found in the Lost Cabin horizon of the Bighorn basin. 
