304 
CARNIVORA. 
Canis ursinus, Cope. 
Plate Ixix, fig. 1. 
Proc. Phila. Acad., 1875, 256 ; Ann. Rept. Chief of Engineers, 1875, ii, p. 988. 
This curious species is the largest carnivorous animal detected in the 
Santa marl, the lower jaw having about the size of that of the Black 
Bear. The outline of the mandible is peculiar in its greater depth poste¬ 
riorly as compared with the Wolf, which is occasioned by the gradual eleva¬ 
tion of the alveolar border and the very slight upward bend of the inferior 
border until it has passed the line of the first tubercular molar. The 
interior face of the ramus is plane, while the exterior is deeply concave 
from below the anterior margin of the sectorial tooth to the line of the 
posterior border of the second tubercular, where the ramus is broken off 
The excavation is below the extremities of the roots of the molars, and is 
bounded below by the everted lower border of the jaw. This border is 
narrow, but thickens forward so as to be massive at the symphysis. The 
anterior mental foramen issues below the middle of the second premolar, 
and the second foramen is below the posterior root of the third premolar. 
The external face, immediately below the tubercular’molars, is convex, 
instead of concave as in C. whederianus and C. lupus. 
The crown of the canine tooth is broken off; its root is oval in section, 
and is of large size absolutely and relatively as compared with the C. lupus 
and other Dogs. The alveolus of one and perhaps the base of that of a. 
second incisor remain. The premolar teeth are quite small, and are sepa¬ 
rated from each other bv short diastemata. The first is one-rooted: the 
fourth is in contact with the sectorial. The latter is a large tooth, exceeding 
in antero-posterior diameter that of both tuberculars together. It has a wide 
posterior heel, but tlie anterior sectorial part of the crown is broken away. 
The first tubercular is a large tooth, with the crown oblong in section, con¬ 
siderably exceeding the last premolar in size. The crown is worn by use. 
The alveolus of the second tubercular remains. It is single, but large and 
compressed, and a keel on its external side shows that the root is grooved. 
Its long axis is directed inward and forward, and is three-fourths as long 
as that of the fourth premolar. 
