280 



FIG. 253. 

 Human vertebral 

 column (in an up- 

 right position ; 

 from the right 

 side). (After H. 

 Meyer.) 



THE EVOLUTION OF MAN. 



right side (without arms); Fig. 252, the 

 entire skeleton from the front.) In Man, 

 as in all other Mammals, the skeleton is 

 primarily distinguishable into the axial 

 skeleton, or spine, and the skeleton of the 

 appendages, or the bony frame of the limbs. 

 The spine consists of the vertebral column 

 and of the skull ; the latter being the pecu- 

 liarly modified anterior part of the former. 

 The ribs are the appendages of the vertebral 

 column; the tongue-bone (os linguae), the 

 lower jaw, and the other products of the 

 gill-arches, are those of the skull. The 

 skeletons of the two pairs of limbs, or ex- 

 tremities, are composed of two different 

 parts : of the bony frame of the actual, pro- 

 minent extremities, and of the inner girdle 

 skeleton, by which the limbs are attached 

 to the vertebral column. The girdle skele- 

 ton of the arms (or fore limbs) is the 

 shoulder girdle ; the girdle skeleton of the 

 legs (or the hind limbs) is the pelvic 

 girdle. 



The bony vertebral column in human 

 beings (columiia vertebralis, or vwtebra- 

 rium, Fig. 253) is composed of thirty-three 

 or thirty-four circular pieces of bone, which 

 lie one behind the other (one above the 

 other in the usual upright position of 

 man). These bones (vertebra} are sepa- 

 rated from each other by elastic cushions, 



