358 IHE WASATCn AND BRIDGER FAUNJ3. 



Besides tlie inferior size, this species apparently differs from the M. 

 lanius in the form of the ungual phalanges. Those preserved are much nar- 

 rower than the single one of the M. lanius that is known. It is, however, 

 not certain that these phalanges were alike on all the digits. 



This species was as large as a wolf. While the proportions of the 

 limbs were not very different, the foi'm was rather more slender behind. 

 The orbit was smaller, and the cheek bone more prominent than in those 

 animals. The long tail added to the general resemblance to the dogs. The 

 narrow navicular facet of the astragalus renders it probable that the inner 

 toe is wanting or rudimental, and that there are four digits on the hind foot. 

 The claws are flat, and altogether without prehensile use, but rather adapted 

 for aquatic life. 



I obtained the bones above described on a bluff of Cottonwood Creek, 

 near Fort Bridger, Wyoming, during my expedition of 1872. All the 

 pieces were found in close juxtaposition, and without admixture of those 

 of any other animal. 



Mesonyx lanius Cope. 



Synoplotiicrium lanius Coi)C. Paleontological Bulletin No. 0, p. 1, August 20, 1872. Proceed. Amer. Pliilos. 

 Soc, 1872, p. 483. Ibid., lS7:t, p. 207. Annual Report U. .S. Geol. Surv. Terrs., 1672, p. 5o7, pis. 5-(j. 



Plate xsvii, fig. 25; Plates xxviii, sxis, figs. 1-6; Plate xsis.a, fig. 1. 



Besides the typical and, so far, the only specimen I have obtained of 

 this species, there is a second probably referable to it in the museum of 

 Princeton College. For the opportunity of examining the latter I am in- 

 debted to the kindness of Professor Guyot. My own specimen is repre- 

 sented by a large part of the skull with nearly complete dentition, the 

 superior molars loose; lumbar and caudal vertebra;; large portions of both 

 fore limbs, including the bones of the feet; smaller portions of the hind 

 limbs and feet. 



The mandibular rami are quite elongate, and indicate a cranium near 

 the size of that of the brown bear ( Ursus arctos). Their form is slender, 

 and they have a long, rather narrow, symphysis, which projects obliquely 

 forwards. The angle is not preserved. The mental foramen is large and 

 issues just behind the canine teeth. 



The dentition is I. 5-r; C. r; M- -;:,■ The canine is of very laree size. 

 10 17 J s> r 



