114 DIN(X'EUATA. 



An anterior view of the niagnuni, when in its natural position among 

 the other bones of the carpus, is seen in Phite XXXIV, figure 1. The 

 dermal surface is pentagonal in outline, rough and tuberculated, while 

 behind and above it, is seen obliquely a portion of the smooth articular 

 face by which the bone articulates with tlie lunar and scaphoid bones of 

 the preceding carpal series. 



The lateral surface of the magnum (figure 2) turned toward the 

 trapezoid varies in the shape and structure of its articular face for that 

 bone. This face is frequently more or less divided, as in the specimen 

 figured, or the articular face may be on the distal part of the bone, not 

 extending across to the scaphoid face. A large proportion of the posterior 

 part of the face for the scaphoid is seen in the same figure. This face is 

 strongly saddle-shaped. In the same view, is seen a third articular face, 

 for the support, in part, of the second metacarpal. Tliis face is narrow, 

 and elongated from before backward, and, in the natural position of the 

 bone, is directed obliquel}' downward, towai'd the radial side of the foot. 



The posterior, or palmar, surface of the magnum (figure 3) is rough, 

 but rounded over, and shows at the upper, or proximal, end a portion of 

 the articular face for the lunar, carried well over on the posterior face of 

 the bone. 



The lateral surface (figure 4) turned toward the unciform presents 

 a considerable, but varying, articular surface for imion with that bone. 

 In the specimen figured (number 1208), there is a large ai'ea extending 

 along the entire length of the proximal, or lunar, articular face, contracting 

 near the middle, but ex2:)anding anteriorly, so as to extend nearly, or quite, 

 across the lateral surface of the bone. In many specimens (numbers 

 1195, 1218, 1219, 1230, 1616), this area is confluent with the distal articular 

 face for the third metacarpal. In the specimen figured, however, it is, 

 interrupted by a sliglit ridge at tliis point, beyond which, it is continued 

 well along the margin of tliis articular face posteriorly. This distal 

 backward extension of the ai-ticular face is not present in all s[)ecimens 

 (numbers 1195, 1230), and is often much narrower than in the specimens 

 figured (numbers 1211, 1219) 



