442 G. I. Adams — Extinct Felidce of North A 



menca. 



ever, a specimen which may be considered as a probable ances- 

 tral form of all the Machserodontinse and brings them a step 

 nearer the Creodonts. It is the jaw fragment from the Bridger 

 Eocene (number 11375 in the Princeton Collections) which 

 Wortman has described as ? Patriofelis leidyanus (Am. Mus. 

 Nat. Hist. Bnll., 1892) as a probable connecting link between 

 the Creodont Pcdeonictis and the Felidse. A further knowl- 

 edge of Patriofelis induced him to remove it from that genus 

 (ibid., 1894). For the sake of reference I propose the generic 

 name JElur other ium. JElurotherium leidyanum, following 

 the description given by Wortman, consists of a jaw fragment 

 containing the third and fourth premolars and the first molar 

 or sectorial. It also bears a distinct trace of the alveolus for 

 the canine, the position of which is such as to preclude the pos- 

 sibility of there being more than three premolars. The sec- 

 torial, as will be seen from a comparison with Dinictis, presents 

 the same elements as that genus but has a much better devel- 

 oped postero-internal cusp and heel, thus fulfilling the require- 

 ment of an ancestral form. From what can be judged from 

 the wear of the cusps and the relation of the teeth in the 

 Felidse it seems probable that it possessed the dental formula 

 Pf M^ as was inferred by Wortman, thus exceeding the dental 

 formula of Dinictis by a premolar. It will be noted that the 

 dental formula of JEhirotherium was probably more primitive 

 than that of Archaelurus, thus not precluding the possibility of 

 its being ancestral to that genus also, although probably quite 

 removed from it. 



The following arrangement according to subfamilies expresses 

 the probable line of descent of each as well as the occurrence 

 in time of the various genera. 



Eocene 

 Bridger 



Olicocene 

 White River 



Miocene 

 John Day Loup Fork 



Pliocene 



Pleistocene 



Recent 





JElurotherium 



EuSMILUS 

 / HOPLOPHONEUS 



Mach^erodus/ 



Smilodon / 



Dinobastis 





1 







Smilodon 







Mach^erodus 



Lynx 







HOPLOPHONEUS / 



Felis / 







/ Dinictis 



Dinictis 





o 





JBlurogale 





h 



s 





\ / 



Archaelurus 





3 



v_ 



Nimravus 

 pseud^lurus 









Lynx 



N 







\ Felis 



Felis 



Felis 



\\ 





V 



Cyn^lurus 



Cyn^lurus 



CyN/ELURUS 



h 





Phosphorites 



St., Gerand Sansan 



LE PUY 



Val d'Arno 







