62 BULLETIN UNITED STATES GEOLOGICAL SUEVEY. [Voir. 



latter is snbtriangiilar in ontHne, its apex being tb.e point of conjunction 

 of the scaplio-lunar ridge mtli the internal border, just posterior to its 

 greatest convexity. Its sni)erior boundary is interrupted by the wide 

 gToove which separates the median ridge from the internal border of 

 the distal part of the radius. 



Measurements of the Ulno-radius. 



M. 



Transverse diameter, total - 0.110 



TraBSverse diameter of ulna 0.050 



[" externally 0.035 



. ^ ,.,. ^ ,.,.10 J at middle of ulna 0.021 



Antero-posterior (bameter oi articular iace\ , , .„ ., r> r^r-,- 



at luno-cuneiform ridge 0.055 



linternally 0.045 



But for the extent and transverse position of the ulnar portion of this 

 articular face, it might be regarded as pertaining to a typical Euminant. 



The length of the carpus is about three-fourths its width, the j)roximal 

 elements being larger than the distal. A feature of its anterior face is 

 the close approximation of the inferior angle of the lunar to the superior 

 angle of the third metacarpus, which allows the magimm and unciform 

 a very slight contact. The external face of the scaphoid is chiefly lat- 

 eral; its posterior border is a vertical, short tuberosity. The proximal 

 face is abruptly decurved at the anterior outer angle, to meet the lunar. 

 There are two separate oval superior lunar facets, and one narrow an- 

 terior inferior one. The inferior face is nearly equally divided by a 

 low cross ridge which fits a concavity of the posterior part of the mag- 

 num. The lunar is the largest bone of the cari)us. Its proximal face 

 is decurved anteriorly, posteriorly, and on each side, and is twice as 

 long as wide at the middle. The postero-internal and antero-external 

 angles are produced, the latter into a comi)ressed process which articu- 

 lates with the adjacent angle of the cuneiform. Besides this facet there 

 is one other for the cuneiform, which occupies the posterior half of the 

 inferior part of the outer side, and is separated from the sujjerior edge 

 by a deep groove. The unciform facet is in front nearly as wide as that 

 of the magnum, but grows gradually narrower i)osteriorly. The facet 

 for the magnmn is concave, and grows very wide X)osteriorly, with the 

 posterior internal angle produced downwards. The proximal facet of 

 the cuneiform is very concave, the anterior and posterior borders being 

 elevated, and the internal and external decurved ; the latter prolonged 

 a little backwards. Below this extremity on the external aspect is a 

 fossa. The jiisiform facet makes an angle of 90° with the ulnar, and 

 extends behind and along the posterior edge of the latter to its apex. 

 The unciform facet is simple, and is in shape a right-angled triangle 

 with convex hypothenuse. The posterior aspect of this bone is concave. 



The proximal face of the trai:)ezoides is longer than wide, convex an- 

 tero-posteriorlj", and subdiamond-shaped. The inferior face is narrow 

 subdiamond-shaped, and has less than half the area of the xjroximal. 

 There is a small romid tuberosity on the i30sterior border, and no trace 



