86 MEMOIRS OF THE CARNEGIE MUSEUM 



the radius, while distally there are four well-defined articular surfaces for contact 

 with the trapezium, trapezoid, magnum, and unciform. The scapho-lunar did not 

 articulate laterally with the pyramidal as in the canidse, but those bones were 

 well separated by the superior, keeled, articular surface of the unciform. The 

 middle, inferior, and anterior surface of the scapho-lunar is produced into a rather 

 extended keel, which is interposed between the trapezoid and external portion of 

 the magnum in such manner as to reduce the antero-internal portion of the latter 

 to a flattened disk, more pronounced even than in the modern felidse and quite dif- 

 ferent from that which obtains in the dogs. 



The pyramidal is very much flattened, much more so than in either the recent 

 canidse or felidse. Inferiorly and posteriorly it is continued into a considerable 

 process which overlaps and gives lateral support to the proximal end of metacarpal 

 V. Inferiorly there is a rather extensive and concave surface for articulation with 

 the unciform. The superior, or external surface, shows two subequal articular sur- 

 faces, separated by a low keel for contact with the pisiform and ulna. 



The pyramidal and ulnar articular surfaces of the pisiform are subequal and the 

 tuberosity is more expanded than in either the modern canidse or felidse. 



The trapezium is decidedly heavier than the trapezoid in marked contrast to the 

 relative proportions, of those bones in the modern dogs. It presents a broad, flat 

 articular surface for contact with M. I., but scarcely articulated with M. II. thus 

 approximating the dogs rather than the cats. 



The trapezoid is a small triangular bone with the apex directed backward. 

 Superiorly it presents to the scapho-lunar an articular surface which is convex ante- 

 riorly and concave posteriorly. On the internal side it articulates with the 

 trapezium, while inferiorly and externally it articulates with M. II. and the mag- 

 num, which it slightly overlaps as in the cats, though its contact with the latter 

 bone is quite limited. The general shape of the bone is cat-like rather than canine. 



The magnum is very much depressed antero-internally, but externally it sends 

 upward a sharp ridge of bone between the unciform and scapho-lunar which pos- 

 teriorly almost entirely separates those bones. Both these characters are feline 

 rather than canine, but both are more emphasized in Daphoenus than in the recent 

 cats, while in the dog the magnum is high in front throughout its entire width and 

 the superior keel or ridge on the supero-external border is less pronounced than in 

 the cats. Distally the magnum presents an articular surface for contact with M. III. 



Next to the scapho-lunar the unciform is the largest bone in the carpus. It is 

 wedge-shaped, with the apex directed upward. It articulates internally with the 

 magnum and scapho-lunar, externally with the pyramidal and distally with M. IV. 



