THE CETACEA, OK WHALES. 



249 



coverings, and stand as perpendicular back walls to 

 the nose, while the frontal and parietal bones are 

 compressed and pushed aside in the most remark- 

 able manner. However, it would certainly not re- 

 quire a practised osteologist to construct the skull 

 of a whale from any certified bone. There is 

 nothing in the skull of the whale that could, in the 



FIG. 45.- Skull of Delphinus lagenorhynchus. Gray. 



z /:, Mid-jawbones ; o k, upper jawbone ; j, cheek-bone ; 

 bone ; n, nasal bone ; e, olfactory bone. One-fi 



1 parietal ; s, frontal 

 nat. size. 



slightest degree, lead to a connection between it 

 and the Sirenians (p. 243). Nevertheless, their hind 

 limbs, like those of the Sirenians, have disappeared 

 externally without leaving a trace of their former 

 existence ; the rudimentary pelvic bones that are 

 concealed in the flesh sometimes with the last rem- 

 nant of the thigh-bone, very rarely with the shank 



