842 On the Extinct Cats of America. { December, 
tition it adds a tooth to the number belonging to that genus, in 
both jaws, and has a smooth-edged canine; it is otherwise identi- 
cal with that genus, unless, indeed, the exostosis supporting the in- 
ferior sectorial tooth in the A. debilis, be introduced into this cate- 
gory; a position I am not prepared to assume positively. There 
is but one species known, the 
Archelurus debilis Cope. 
It is probable that this was an anima: presenting much the ap- 
pearance of the existing cats, and of about the size of the Ameri- 
can panther. Omitting more technical characters, it differed from 
this and other species of the Feide in the greater slenderness of 
its feet. Its head was characterized by less breadth through the 
posterior part of the cheeks, and by a greater convexity of the 
forehead between the eyes, and a greater prolongation backwards 
of the same region. 
Its structure plainly indicates that this species was of less san- 
guinary habits than the existing Fc/id@, since its prehensile 
organs, both of the feet and dentition, are less robust. The slen- 
der zygomata and rami of the lower jaw show also that the 
impact of its bite was less powerful, although the large size and 
narrow form of the sectorial teeth, furnish an effective cutting 
apparatus, which in some degree supplements the deficiency of 
strength. The weakness of the rami is further provided against 
Fic. 3.—Archeiurus debilis, one-half natural size. Mus. Cope. From Vol. Iv, 
e of U. S. Geol. Surv. Terrs. 
by the curious exostosis at the base of the inferior sectorial, 
already mentioned ; see Fig. 3. 
