SPERM WHALES 193 



an extent as in the Cachalot. The expansion, 

 elongation, flattening, and distortion of many of the 

 cranial bones, met with in a certain degree in all 

 Cetaceans, is here carried so far as to render it by 

 no means easy, at least in the adult animal, to 

 recognise their homologies." 



In the first place the skull is enormously large 

 in proportion to the rest of the body, larger than in 

 any whale (and a fortiori than in any mammal). 

 The Greenland whale does not really form an 

 exception. It is certainly rather longer in proportion, 

 but it is not so massive. The skull is raised into a 

 great crest behind the vertex, being occupied by the 

 maxilla and frontals. The asymmetry is chiefly 

 shown in the pre-maxillae and the nasals. The right 

 pre-maxilla is very much the larger. The left nasal 

 alone is present. 



The parietal bone, if not suppressed, is represented 

 merely by a wedge-shaped piece of the supra-occipital. 

 The orbit has unusually solid margins, more so than 

 in any toothed whale ; this is due to the large size 

 and solidarity of the jugal, which, however, is not, 

 as it is in the Ziphioids, divided into two pieces. 

 The entire bone apparently represents the separate 

 malar and lacrymal of the Ziphioids. 



The pterygoids meet for a considerable distance 

 in the middle line ; the vomer is entirely exposed in 

 front of the palatines. The two rami of the lower 

 jaw do not appear to be united at the symphysis by 

 ankylosis ; the length of the symphysis recalls the 

 Platanistidae. 



