388 ME. E. W. HOOLEY OS THE [June I9I3,. 



extending some distance down the bone. The crown of the ridge 

 is highest near its distal termination, and its top bends over, 

 forming on its preaxial side a slightly-concave surface, against 

 which the radius rested. The section of the bone here, minus the 

 ridge, is circular, gradually becoming oval in the median region 

 of the shaft, and this in its turn gives place to a quadrangular 

 section as the distal end is approached. At the distal end the 

 bone is expanded pre-postaxially: the dorsal surface is fiat, the 

 ventral concave, and the pre- and postaxial borders convex, although 

 these surfaces have raised and concave areas. On the dorsal 

 surface, towards the postaxial border, is a longitudinal ridge- 

 (Pl. XXXIX, fig. 5, ri.) : against it the radius lies, and is thus 

 supported and stiffened by a ridge on the postaxial ventral, 

 surface of the proximal end, and also by a similarly-placed ridge 

 on the dorsal surface of the distal end. On the ventral side, 

 near the postaxial border at the distal extremity, is a circular 

 facet (PL XXXIX, fig. 6, fa.) with a flat articular surface raised 

 above the bone, placed obliquely, looking preaxially, and continuing 

 distally to a convex condyle on the articulation. This forms a very 

 prominent feature. The preaxial border is very deep ; 40 mm. 

 from the distal end its dorsal margin is produced into a wing, 

 which, rapidly expanding outwards, extends to the distal end r 

 here the whole border is swollen, and terminates in a tubercle 

 directed distally and moderately produced. By this arrangement,. 

 on the distal preaxial border an elongated concavity is formed; 

 this has a roughened surface, and forms the insertion for a 

 powerful tendon. 1 The postaxial distal border is convex, and is 

 not expanded outwards to as great an extent as the preaxiah 

 As at the proximal end, the distal extremity comprises the whole- 

 of the pre-postaxial extent of the articulation. Here the radius 

 articulates dorsally to the ulna. On the articular surface of the 

 distal extremity, postaxially to the tubercle, a deep, circular, basin- 

 shaped pit occurs ; this is followed by a trochlear joint extending 

 to the postaxial border. The inner condyle of this trochlea is an 

 oval-shaped convexity, situated medially, with its long axis directed 

 pre-postaxially. The convex outer condyle is continued obliquely 

 on to the ventral surface of the shaft, where it looks preaxially. 



The Carpus. 



The carpus consists of three distinct bones— a proximal, a distal, 

 and a lateral carpal. The proximal and distal carpals are much 

 wider than long, and the lateral longer than wide. The proximal 

 articular surface of the proximal carpal is greater in area than the 

 distal, causing the outer face of the bone on all sides, more or less, 

 to slope inwards, towards the distal articulation ; in the distal carpal 

 this feature is reversed, and thus there is a constriction towards 



1 For the guidance of future students of this specimen, I may mention that 

 this area of the right ulna was accidentally excavated too much when the 

 bones which covered it were being freed from the matrix. 



