xo. 166G. OSTEOLOGY OF CAMPT08AURU8—GILM0RE. 253 



smooth, concave proximal end forming the chief support of the ulna. 

 The anterior surface is convex transversely, Avhile the posterior is 

 concave. It articulates with the intermedium by two facets on either 

 extremity of the internal border. The intervening border being con- 

 cave is not in contact with that of the intermedium. 



There are five small elements in the distal row of the carpus. 

 Carpale one is a small ossicle-like bone wedged in between the ends 

 of Metacarpal I and the radiale on the posterior side. It is not 

 visible from the front aspect. In the forefoot of specimen No. 5473, 

 this element was in position but remained as a distinct bone. In No. 

 4277, however, it is fused wnth both the radiale and Metacarpal I 

 and is hardly recognizable. 



The second carpale in No. 4277 is a small, flattened, rectangular 

 element which was retained in position on the proximal end of Meta- 

 carpal II. Its thin, anterior border is visible in fig. 29 between the 

 radiale and Metacarpale II. 



The third carpale is a wedge-shaped element coossified about 

 equall}^ with the posterior part of the surfaces of the radiale and 

 intermedium. It articulates slightly with Metacarpal III, and al- 

 though in other specimens it is visible from a front view of the foot, 

 in this one it is not. 



Carpale five, seen from the front, is a lozenge-shaped element 

 interposed between the outer distal surface of the ulnare and the 

 proximal end of INIetacarpal V. Marsh has represented this element 

 in the foot of C. dispar as contributing to the ulnar surface, but in 

 the specimen here described, an outer extension excludes it from the 

 ulnar surface. 



The metacarpus. — Metacarpal I is much the shortest element of 

 the series and in adult individuals is always fused with the radiale. 

 The inner border of the proximal end rises to the level of the dorsal 

 surface of the radiale and contributes slightly to the articulating 

 surface for the radius. The distal end is convex dorso-ventrally 

 with a pronounced median depression or groove. The short shaft 

 is angular in cross section, being wider than deep. Fore and aft 

 on the external lateral margin of the proximal end are two antero- 

 posteriorly elongated facets Avhicli articulate with corresponding 

 facets on the internal margin of Metacarpal II. 



Metacarpal II is more than twice the length of the preceding 

 and more slender. The proximal end is subtriangular in outline, 

 its antero-posterior diameter being the greater. The articular sur- 

 face of this end is comparatively smooth and gently convex antero- 

 posteriorly. The shaft is somewhat constricted but expands again 

 at the distal end, more especially in its transverse diameter. The 

 external border of the distal end is produced distally below the 

 internal, which deflects the phalanges of this digit mesially. The 



