OSSEOUS SYSTEM OF MAMMALIA. 



is it needful to linger over the scapula and the humerus. But our 

 attention is arrested by the bones of the fore-arm, which, in the 

 solidungulous group, and in the ruminants, offer a conformation very 

 unlike what has hitherto been noticed ; inasmuch as they generally 

 constitute only a single bone. In the Elephant, however, the Rhinoceros, 

 the Hog, the Tapir, and the Hippopotamus, the radius, a, and the 

 ulna, 6, are perfect ; the ^former bone assuming an anterior position to 

 its associate. The carpus, c, consists of short, thick, solid bones (eight 

 in number in the Elephant), with which are articulated those of the 

 metacarpus, five in number in the Elephant, and 

 four in the Hog, the Tapir, and the Hippopotamus, 

 corresponding to the. number of the toes. In the 

 Elephant, Tapir, and Hippopotamus, the toes are 

 very short, and almost buried in the skin : in all, 

 they are sheathed at their extremity with hoofs, or 

 hoof-like nails. It is on these hoofs, which tip the 

 last bone of the toes, that the Hog rests ; the re- 

 maining bones (that is, the other phalangal bones 

 the carpal and the metacarpal) bearing nearly per- 

 pendicularly upon this point. 



Fig. 96 represents the foot of the Hog: a, a, 

 the two large middle metacarpal bones ; b, the pha- 

 langes, following them ; c, the small lateral metacarpal bone, to which 

 another on the opposite side corresponds ; d, the phalanges of the small 

 lateral toe, those on the opposite side being only partially seen. 



By way of contrast, the fore limb of the Horse, a solidungulous 

 97 animal, that is, in which the digits are all consoli- 



dated into one, may be next noticed. Here the 

 fore-arm, a (fig. 97), consists of a single bone ; 

 made up, it is true, of an ulna and radius ; but the 

 ulna is only to be traced in the olecranon process, 

 6, shewing itself as a fixed appendix to the radius, 

 c. The carpus, d, consists of seven bones (four in 

 the first row, three in the second) : to these succeeds 

 a long metacarpal bone, in one solid piece, known by 

 the name of the canon bone, e ; and to this succeed 

 three phalangal bones,/, forming one digit: the first 

 is termed the pastern ; the next, the coronet, or 

 crown bone (both often termed pastern bones) ; and 

 the last, the coffin bone, which is enclosed in a hoof 

 of thick, firm horn : on this the Horse treads, and with an elastic step ; 

 a circumstance resulting from the oblique position of the bones of the 

 leg and foot, but especially from the yielding of the pastern, its elasticity 



Lateral view of the bones of 

 the foot of the Hog. 



b of the Horse. 



