136 Bulletin Atne7-ican Museum of Natural History. [Vol. XII, 



VIII. — ViVERRAViD^, fam. nov. 



This family is proposed to include the species which have been 

 formerly arranged under the genus Didymictis of Cope. That this 

 genus is synonymous with the one previously established by 

 Marsh, there cannot be the slightest question whatever. A care- 

 ful comparison of the type of Viverravus gracilis Marsh,' with 

 the type of Didymictis dawkinsianus "^ Cope, reveals the fact that 

 they are identical in every detail ; the name Didymictis must 

 therefore be abandoned and the name Viverravus substituted for 

 the genus. 



It has been customary to associate this group of species, together 

 with that which has been referred to Uintacyon {Aliacis), in the 

 family Miacidce. We have already shown that this latter is clearly 

 related to, and no doubt ancestral to the Dap/ice/ius, the Cyon 

 section of the Canidae. It is also evident from much additional 

 material now in the Museum collections that Viverravus belongs 

 to an entirely distinct line and has no relationship with the Canidae 

 whatever, but in so far as the skeleton can be depended upon for 

 evidence of affinity it finds its nearest relationship with the living 

 Viverridae. This opinion is not a new one, having been first ex- 

 pressed as long ago as 1886,^ and later in 1891.'' 



The new evidence consists of the greater part of a skeleton of 

 Viverravus protenus from the Wasatch Eocene of Wyoming, to- 

 gether with a considerable portion of a skeleton of V. leptomylus 

 from the same horizon. The skull, of which there is a fairly well- 

 preserved example, shows many striking resemblances to the more 

 typical Viverrines, especially Viverricula ; it is long and narrow, 

 with prominent overhanging occiput and high sagittal crest. The 

 muzzle is long, the basilar portion of the skull is narrow, and the 

 mastoid not very prominent. The tympanic bulla is not preserved, 

 but the general conformation of this part of the skull is very 

 Civet-like. The lower jaw is long and relatively slender, with 

 high coronoid and prominent angle. The dental formula, as is 

 well known, is that of the Viverridae, and the pattern of the teeth 

 resembles most astonishingly that of the more typical members of 



• Amer. Jour. Sci. 1872 (p. 7 of separate). 



« Bull. U. S. Geol. Surv. VI, 1881, 191. 



^Wortman, Teeth of the Vertebrata, 457. 



■* Flower and Lydekker, Mammals Living and Extinct, 539. 



