82 



LAND MAMMALS IN THE WESTERN HEMISPHERE 



der, more or less of its middle portion is lost and the two ends 

 are coossified with the radius, so that the fore-arm appears to 

 have but a single bone. The reverse process of enlarging the 

 ulna and reducing the radius is very rare and practically con- 

 fined to the elephant tribe. 



The fore foot, or hand, for which the term manus may be 

 conveniently employed, is divisible into three parts, correspond- 

 ing in ourselves to the wrist, back and palm of the hand, and 

 the fingers. The bones of the wrist constitute the carpus, 



Fig. 33. — Left manus of Man. S., sea 

 phoid. L., lunar. Py., pyramidal (pisi- 

 form not shown). Tm., trapezium. Td., 

 trapezoid. Af., magnum, f/n., unciform. 

 Other letters as in Fig. 32. 



Fig. 32. — Left manus of Wolf, front 

 side. SL., scapho-lunar. Py., pyram- 

 idal. Pis., pisiform. Tm., trape- 

 zium. Td., trapezoid. M., magnum. 

 U., unciform. Mc.I-V, first to fifth 

 metacarpals. Ph.l, first phalanx. 

 Ph. 3, second phalanx. Ung., ungual 

 phalanx. /, first digit, or poUex. II-V, 

 second to fifth digits. 



those of the back and palm the metacarpus, and those of the 

 fingers the phalanges. 



The carpus consists primitively of nine distinct bones, 

 though one of these, as will be shown later, is not a true carpal. 

 These bones are of a rounded, subangular shape, closely ap- 



