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, 



yfia. 



Fig. 32. — Left manus of Wolf, front Fig. 33. — Left manus of Man. S., sea 



phoid. L., lunar. Py., p3rramidal (pisi- 

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

 trapezoid. JIf., magnum, [/n., unciform. 

 Other letters as in Fig. 32. 



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

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

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

 v., unciform. Mc.I-Y, first to fifth 

 metacarpals. Ph.l, first phalanx. 

 Ph.2, second phalanx. Ung., ungual 

 phalanx. 7, 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- 



