602 The American Naturalist. [July, 
9. Dipriodon lunatus (Pl. 11., Figs. 16-18). The typeis rightly 
described as a first or second upper molar—Keeping in mind the 
larger size and greater complexity of the more anterior molars, 
there is no ground for referring it to a new species. 
10. Tripriodon celatus (Pl. 1., Figs. 19-21). The type is 
described as a first upper molar, and is referred to a new family, the 
Tripriodontidae.—It resembles in the arrangement of its denticles 
the lower molars of Stereognathus, and, as shown below, is a last 
lower molar belonging to the genus Meniscoéssus Cope. 
11. Selenacodon fragilis (Pl. 11., Figs. 22-24). The type is 
described as an upper molar distinguished by crescentoid tubercles 
from the foregoing.—It is an anterior lower molar belonging to 
the genus Meniscoéssus Cope. 
12. Selenacodon brevis (Pl. vii., Figs. 9-12). The type is 
described as an upper tooth, apparently from the left side—As 
the accompanying figures show, it agrees in every detail, except 
the degree of wear, with the type of Menzscoéssus conquistus Cope ; 
it is a lower molar, probably the last. 
The lower incisor (PI. vii., Figs. 1-3) is probably correctly 
referred. ` 
13. Tripriodon caperatus (Pl. 111., Figs. 18—20). The type is 
correctly described as a lower incisor.—No ground is assigned for 
referring it to a new species. Similar incisors of smaller size (Pl. 
11., Figs. 21-22; Pl. vur., Figs. 1—3) are referred respectively to 
Tripriodon celatus and Selenacodon brevis. 

Fic. 5, 
robustus, cr 
dontidze’ de), es 


