G. I. Adams — Extinct Felidce of Worth America. 441 



Felidse, and the absence of the cusp is not of sufficient import- 

 ance, as would be judged by the absence of the same character 

 in certain of the Machserodontinse. 



The subfamilies may be defined as follows, slightly modify- 

 ing Gill's definitions : 



Machserodontinse ; superior canines large and powerful, 

 usually saber-shaped with posterior and anterior denticulate 

 borders, the inferior canine not greatly exceeding the outer 

 incisor. Symphysial portion of the mandible separated from 

 the lateral surface by an angle, the anterior inferior border of 

 the ramus produced into a flange or making an obtuse angle 

 with the symphysial portion. 



Felinge. — Canines sub-conical and sub-equal, inferior and 

 lateral faces of ramus continuous with the symphysial. 



The Machserodontinse as thus constituted include a group 

 which is in some respects intermediate between the two sub- 

 families but which do not stand ancestral to any genera of 

 either of them and are not derivable from them. They are 

 Archcelurus, the European genus ^Elurogale and the peculiar 

 JVimravus. Archcelurus and JVimravus have been called by 

 Cope the " false-sabre-tooths." Archcelurus in general appear- 

 ance is very suggestive as to what was the probable ancestor of 

 the Machserodontinse, but its late appearance and specialized 

 tooth structure show that it could not have given rise to any 

 known form outside of the genera above mentioned. On the 

 removal of the matrix from one of the specimens I found that 

 the internal cusp of the superior sectorial is wanting in Archce- 

 lurus. The same also proved to be true in JVimravus, although 

 reported as present in each by Cope. Moreover the postero- 

 internal cusp of the inferior sectorial is wanting in JVimravus 

 and probably in Archcelurus. Thus there is found to be the 

 same tooth-structure in these two genera that is seen in ^Elu- 

 rogale. It is therefore demonstrated that although the denti- 

 tions of these genera are more primitive as regards numbers, 

 they could not have given rise to other Machaerodonts or to 

 the Felinge. These three genera are related in the order of 

 the reduction of the dental series, the character of the man- 

 dible and the structure of the canines. The canines of Archce- 

 lurus have a convex anterior border and a posterior cutting 

 edge, but in its present state of preservation shows no signs of 

 denticulations. The canine of JElurogale has the posterior 

 border denticulate. The peculiar spike-shaped canine of Nim- 

 ravus is very suggestive that this genus marks the end of an 

 aberrant phylum. 



The subfamilies stand entirely distinct from each other and 

 well separated from the Creodonts. In the subfamily Machsero- 

 dontinae there is, as has just been shown, a small group which 

 stands in a peculiarly isolated position. There is, how- 



