154: SKELETON OF THE WHALE. 



together into a single bone ; they thus give a firm and 

 unyielding support to the large head, which has to over- 

 come the resistance of the water when the rapid swimmer 

 is cleaving its course through that element. The dorsal 



Eiff. 25. 



FORESHORTEXED VIEW OF THE SKELETON OF A WHALE {BcilcBlloptera hoops), 

 SHOWING ITS RELATIVE SIZE TO MAX. 



vertebrae are characterized in all mammalia by the sudden 

 increase in the length and size of the ribs, which, in a 

 certain number of these vertebrae, including the first, are 

 joined to a breast-bone by a commonly cartilaginous, 

 rarely osseous, part. The first rib is remarkable for its 

 great breadth in the whale ; this and a few following ribs 

 are joined to a short and broad and often perforated ster- 

 num (Fig. 25), No. 60 ; the remaining ribs are free, or, ^s 

 they would be called in Human Anatomy, " false." They 

 are articulated to the ends of diapophyses, which pro- 

 gressively increase in length to the last of the dorsal 

 series. Then follow vertebrae without ribs, answering to 

 those called "lumbar." The whole hinder part of the 

 trunk of whales being needed to effect the strokes by 

 which they are propelled, its vertebrce are as free from 

 anchylosis as in fishes; there is consequently no "sacrum," 

 and the caudal vertebrae are counted from the first of 



