HISTORY OF THE CARNIVORA 527 



more retractile and the gait was probably more plantigrade. 

 There were so many cat-like features in the skeleton of fDa- 

 ■phoenus, that the observer cannot but suspect that these resem- 

 blances indicate a community of origin, but, until the Eocene 

 ancestors of the cats are found, the question of relationship 

 must remain an open one. 



The most ancient member of the bear-dog phylum yet 

 discovered appears to be one of the fcreodont family of the 

 fMiacidae, found in the Uinta Eocene. 



A short-Uved branch of the canine stock was that of the 

 so-called "fhyena-dogs," a peculiar American type, which 

 abounded in the upper Miocene and lower PUocene and then 

 became extinct. Traced backward, this brief series of species 

 would appear to have sprung from the true wolves {\Tephro- 

 cyon) of the middle Miocene. The upper Miocene and lower 

 Pliocene genus ^Mlurodon had several species, which differed 

 considerably in size ; the commoner of these were large wolves 

 with very modern type of body, tail, limbs and feet, but having 

 short and massive heads. The premolars were extremely 

 thick and heavy, with such a resemblance to those of the hyenas, 

 that these animals have sometimes been mistakenly regarded 

 as ancestral to that family. The especial characteristic, how- 

 ever, of the series was in the form of the upper sectorial tooth, 

 which was much more feline than canine in construction and has 

 given occasion for the generic name which means "cat-tooth." 



A fourth phylum of the Canidae, which would seem to be 

 represented in the modern world by the Indian Dhole, or Wild 

 Dog (Cyon), and perhaps by the Brazilian Bush-Dog {Icticyon), 

 was characterized by the lower sectorial molar, the heel of which 

 was not basin-Uke, as in the tjrpical dogs, but trenchant and 

 consisted of a single sharp-edged cusp, the external one of the 

 primitive basin. Although there is no inherent improbabiUty 

 in the view that the Dhole and the Bush-Dog are derivatives 

 of this phylmn, no positive statement can yet be made, for 

 the gap in the history is too great to be bridged with any assiu*- 



