320 PROCEEDINGS OF THE ACADEMY OF [1892. 



astragalus in some species is slightly grooved, in others not at all; 

 the neck is long, the head narrow and not articulating with the 

 cuboid. The calcaneum is short and stout, with very small sustenta- 

 culum and prominent process for the cubo-calcaneal ligament. The 

 cuboid is like that of Cynogale, but is without the distinct excava- 

 tion for the navicular. Tlie metatarsals, probably five in number, 

 are very slender and interlocked much as in the viverrines. 



Eight species: D. lidydemmms Cope and D. primus Cope, are from 

 the Puerco ; D. jyrotenus Cope, D. leptomylas Cope, D. dawkinsianus 

 Cope, D. massetericxis Cope and D. curtldens Cope, are from the 

 Wasatch, while D. aliidens Cope is from the Wasatch and Bridger. 



MIACISi Cope. 

 Syn. ? Vulpavits'- Marsh, Uintacyori^ Leicly. 



Vulpavus is an older name than Miacis, but being founded solely 

 upon the upper tubercular molars, it cannot be used, for the exact 

 generic reference of the tubercular molars is at present impractic- 

 able. 



The dental formula of the mandible is : I-r Ct Pt M3. The in- 

 cisors are closely crowded together and the second one is pushed back 

 out of the Hue of the other two. P^ is single rooted and in some 

 species is isolated by a diastema both in front of and behind it, in 

 others the dental series is uninterrupted. In mi the trigonid is of 

 moderate height, and through the flattening of the protoconid a more 

 efficient sectorial blade is formed than in Dldymictis ; the talon is 

 basin-like, with distinct hypo- and entoconids. M^ is a " tuber- 

 cular " molar, but retains all the elements of m^. M^ is very small 

 and is sometimes implanted by one fang, sometimes by two. 



The mandible, the only known portion of the skull, varies from 

 the long and slender jaw of 3/. edax to the relatively short, deep and 

 thick jaw of il/. hathygnaihus, with its steeply inclined and abruptly 

 rounded chin ; the masseteric fossa is deep and the angular process 

 a short hook. A few skeletal fragments of M. bathygnaihus have 

 been found, but as the relations of that species to the others, are 

 very far from clear, the description of these will be omitted. 



Six species : 31. parvlvorus Cope, M. {Ulntacyon') edax Leidy, M. 

 ( Uintacyon) vorax Leidy, and 3L hathygnatlius Scott, are from the 

 Bridger horizon. M. canavus Cope has been found in the Wasatch 



1 Proc. Am. Phil. Soc. lH72. p. 470. 



2 Am. Journ. Soc. and Arts, 3rH Sen, Vol. TI, 1871, p. 124. 



3 Proc. Acad. Nat. Sci. 1872, [1873], p. 277. 



