ZOOLOGY. 



25, There are usually four limbs present, but the whale 

 tribe have only the front pair. On this account the 

 mammalia are often called quadru- 

 peds. This term, however, would also 

 include the amphibia and most reptiles. 

 The fore limb is joined to the trunk 

 by the scapula or shoulder blade, and 

 the clavicle or collar bone. The upper 

 part of the limb consists of a single 

 bone, called the humerus ; the lower 

 part of two bones, the radius and 

 ulna ; then follow the carpal or wrist 

 bones, the metacarpal bones, which 

 form the upper part of the hand, and 

 the phalanges, or bones of the fingers 

 or toes. 



The parts of the hind limb are simi- 

 lar to those just mentioned ; but they 

 are called by different names. The 

 hind limb is joined to the trunk by a 

 number of bones, which are generally 

 anchylosed together, and termed the 

 innominate bone. To this is joined 

 the femur or thigh bone ; then the leg 

 bones, tibia and fibula; the tarsus 

 or ankle bones; the metatarsus, or 

 bones of the foot; and the phalanges 

 a, clavicle or collar- of the toes. There are usually five 

 fei^oTrhumeru" 1 ; digits, with three phalanges in each. 

 d, radius ; e, ulna;/, car- The horse, however, has only one 



pal or wrist-bones; g, ,. ., ,. 7 , ,, j n 



metacarpus or bones of digit, corresponding to the middle 

 finger. The ox has bones corre- 

 sponding to two fingers; and there 

 variations from the rule found in some of 



FIG 5. FORE LIMB OP A 

 MAN. 



the hand ; h, phalanges 

 or finger-bones. 



are other 

 the carnivora. 



26. Digestion. Except the Baleen whale and the great 

 ant eater, all mammals possess teeth, which are inserted 

 in distinct sockets in the jaws. They have generally two 



