TO THE LOWER ANIMALS. 105 



characters of each, we must look below the skin, and com- 

 pare the bony framework and its motor apparatus in each 

 (Fig. 19). 



The skeleton of the hand exhibits, in the region which 

 we term the wrist, and which is technically called the 

 carpus two rows of closely fitted polygonal bones, four 

 in each row, which are tolerably equal in size. The bones 

 of the first row with the bones of the forearm, form the 

 wrist or joint, and are arranged side by side, no one 

 greatly exceeding or overlapping the rest. 



The four bones of the second row of the carpus bear 

 the four long bones which support the palm of the hand. 

 The fifth bone of the same character is articulated in a 

 much more free and moveable manner than the others, 

 with its carpal bone, and forms the base of the thumb. 

 These are called metacarpal bones, and they carry the 

 phalanges, or bones of the digits, of which there are two 

 in the thumb and three in each of the fingers. 



The skeleton of the foot is very like that of the hand 

 in some respects. Thus there are three phalanges in each 

 of the lesser toes, and only two in the great toe, which 

 answers to the thumb. There is a long bone termed mel- 

 alarsal, answering to the metacarpal, for each digit ; and 

 the tarsus which corresponds with the carpus, presents 

 four short polygonal bones in a row, which correspond 

 very closely with the four carpal bones of the second row 

 of the hand. In other respects the foot differs very widely 

 from the hand. Thus the great toe is the longest digit 



carpus and the metacarpus; 6 b that between the latter and the proximal pha- 

 langes ; c c marks the ends of the distal phalanges. The line a' ' in the foot 

 indicates the boundary between the tarsus and the metatarsus ; b' b' marks 

 that between the metatarsus and the proximal phalanges ; and c' c' bounds 

 the ends of the distal phalanges : ca, the calcaneum ; as, the astragalus ; *<?, 

 the scaphoid bone in the tarsus. 

 5* 



