1892.] NATURAL SCIENCES OF PHILADELPHIA. 315 



The humerus has tuberosities of no great size, but the deltoid 

 ridge is remarkably long and prominent ; the trochlea is low but 

 broad and has a rounded surface for the capitellum of the radius; 

 the entepicondyle is relatively small, but retains the foramen. The 

 head of the radius is discoidal and the distal end is expanded and 

 bears a carpal facet which is very feline in shape. The distal end 

 of the ulna has also very much the same form as in the cats. The 

 carpus is low and broad, with separate scaphoid, lunar and central 

 elements. The metacarpals, five in number, are stiikingly small and 

 weak, as compared with the size of the skull and teeth ; they are, 

 however, interlocked in the same elaborate manner as in the cats. 

 The phalanges are depressed and the unguals small, compressed and 

 claw-like, but cleft at the free end. 



The pelvis differs from that of the typical creodonts in having 

 an expanded ilium and wide, flattened ischium. The femur has a 

 wide and flat proxfmal end, and prominent first trochanter, but the 

 digital fossa is small and shallow. The tibia has abroad, overhang- 

 ing head and the shaft is deeply grooved on its posterior face ; the 

 astragalar surface is nearly flat and the inner malleolus prominent. 

 The astragalus has a very slightly grooved trochlea, large neck 

 and convex head, which is directed obliquely inward ; distally there 

 is a facet for the cuboid. The calcaneum is short and heavy and 

 especially remarkable for the great obliquity of thecuboidal surface. 

 The navicular is broad and very shallow and is obliquely placed 

 with reference to the axis of the foot. The cuboid is a remarkable 

 bone and its shape is characteristic of the entire family ; the prox- 

 imal surface is unequally divided between a large surface for the 

 calcaneum and a smaller one for the astragalus which meet at right 

 angles ; this gives the cuboid a very oblique position and causes the 

 axes of this bone and of the navicular to form an acute angle, 

 instead of being parallel. This divergence is to some extent compen- 

 sated by the very large wedge-shaped ectocuneiform. The position 

 of the tarsals here described produces a divergent, radiating arrange- 

 ment of the metatarsals, which like the metacarpals, are all present, 

 but are weak and slender. 



Three species : 0. forcipata Cope, 0. lupina Cope and 0. morsi- 

 tans Cope. Wasatch. 



