Prof. E. D. Cojje — A New Perissodactyle Ungulate. 51 



olfactory lobes were entirely uncovered by them. The bones of the 

 two carpal rows alternate with each other, and there is a third 

 trochanter on the femur. The cervical vertebras are opisthocoelous. 

 The systematic position of the genus may be schematically represented 

 as follows : 



Order Perissodactyla.. Ungulate ; digits of unequal lengths ; 

 carpal bones alternating ; a postglenoid process. Astragalus with 

 proximal trochlea, and without distal double ginglymus. 



Suborder Diplarthra. Astragalus distally plane or concave in one 

 direction, and uniting with both navicular and cuboid bones ; a 

 third trochanter on the femur. The known families belonging here. 



Suborder Condylarthra. Astragalus convex in all directions 

 distally ; only uniting with navicular bone ; a third trochanter on 

 the femur. 



Family PhenacodontidcB. Molar teeth tubercular ; the premolar 

 teeth different from the molars ; five digits on all the feet. 



Genera : Phenacodus, Cope, and very probably Catathlceus, 1 

 Mioclcenus, and Protogonia, 2 Cope ; and perhaps also Anisonchas, 

 Cope. These genera include fifteen species, all from the Lower 

 Eocene beds. The Condylarthra are then the ancestral type of the 

 known Perissodactyla, that is, of the Horses, Tapirs, and Khinoceroses, 

 and of the numerous extinct forms." 



Prof. Cope arrives at the following conclusions as to the measure- 

 ments of the entire animal as figured (see Plate II.). " The measure- 

 ments of Phenacodus primcevus show that this species was as lai'ge as 

 a < Big-horn'; 3 that its body was rather longer than in that animal, 

 and its legs shorter and more robust. It was in fact proportioned 

 more as in the common American Tapir, but was of smaller size. 

 The middle three toes of both feet reached the ground, whilst the 

 first and fifth pi-ojected laterally and posteriorly, like the dew-claws 

 of the Hogs. The tail was longer and heavier than that of any of 

 the living hoofed mammals, resembling in its proportions that of the 

 Wolf. The eyes were small and the muzzle long, but was singularly 

 soft above and near the extremity. Whether this soft part was 

 pierced by valvular muscles, as in the Hippopotamus, or was produced 

 into a short proboscis, as in the Saiga (Antelope) or in the Tapir, 

 cannot be certainly ascertained, but there are indications of the 

 insertion of important cartilages, if not muscles, on the superior 

 faces of the premaxillary bones. 



The animal was probably omnivorous in its diet. It was not 

 furnished with any weapons of offence or defence pertaining to the 

 osseous system, so that it must have sought refuge in flight. The 

 well-developed muscular insertion of its limbs, and the digitigrade 

 character of its step, indicate that it may have had considerable 

 speed." 



" Distribution. — The bones of this species have been found wher- 

 ever the beds of the Wasatch Epoch occur, but most abundantly in 



1 American Naturalist, October, 1880. 



2 Proceedings American Philosophical Society, September, 1881. 



3 Ovis Canadensis, "The Rocky Mountain Sheep." 



