1880. ] _ On the Extinct Cats of America. 837 
front of the ramus of the lower jaw. (9) In the development of 
cutting lobes on the posterior borders of the larger premolar teeth. 
Fic. 1.—Proelurus julieni Filh.; two-thirds nat. size. From Filhol. 
(1) The reduction in the number of molar teeth. The dental 
formula of Proglurus is that of some Viverride and Canide, and 
the reduction from this point to the end of the series is obvious. In 
Lusmilus, as in Smilodon, the number of molars is less by one in the 
inferior series, than in Lynx and Neo- 
Jelis, where the formula is the smallest 
nown among Fé/ide@ proper, viz: $ i- 
(2) The enlarged size of the superior 
canine teeth. In Proelurus and Pseu- 
delurus, the canines of both jaws are 
Subequally developed as in recent Fe- Base... ' 
lide. In Archelurus the superior is Fic. 2,—Proelurus julien Filh.; 
the larger, but does not, relatively to of E nihe: g grieta view of 
the molars, exceed that of Feis. It perrel teeth; ¢ ned sectorial, 
is rather compressed in form, and has si a ogc ma 
a sharp cutting edge posteriorly. In Mémravus the superior 
canine begins to have the enlarged size of the sabre-tooths, 
but its form is peculiar in the W. gomphodus, being spike-shaped 
rather than sabre-shaped. We find the true sabre-shape first 
in Dinictis, where it is compressed, and with a denticulate 
cutting edge on both front:and rear. In Pogonodon it has 
reached a very large size, and it does not display much in- 
crease in this respect until we reach the last genus of the series, 
