322 ME. W. H. TLOWEE ON THE OSTEOLOGY OF THE SPEEM-WHALE. 



inclies. 



Width of rostrum at middle 47 



Eight maxillary 13 



-1 o 



Left maxillary J-"^ 



Eight premaxillary 9 



Left premaxillary .... 9 



Space between premaxillaries 2 



Width of rostrum at three-quarters distance from base 21 



Eight maxillary " 



Left maxillary 2 



Eight premaxillary 8 



Left premaxillary 04 



Space between premaxillaries 2 



Premaxillaries extending beyond maxillaries 22 



vomer 43 



Antero-posterior length of orbital process of frontal 21 



Length of jugal 29 



Height of occipital crest above the bottom of the great supracranial 



basin behind ethmoid 42 



Height of occipital crest above upper edge of foramen magnum . . 35 



Width of occipital condyles 23| 



Height of right condyle (vertical) 14J 



Width of foramen magnum at upper end, between condyles .... 8 



The crania of the different skeletons presented no very marked distinguishing features, 

 beyond such as might depend upon age or individual peculiarity. Of the adult, or 

 nearly adult specimens, those from Caithness and Tasmania are most alike, the former, 

 however, being rather larger and, especially, higher in the occipital crest. The York- 

 shire specimen differs fi-om both in the greater development of the rostrum, which is 

 both broader and longer than in the others : and on this chiefly depends the immense 

 size attained by this gigantic skull ; for the portion of the cranium behind the antorbital 

 notches is of exactly the same length as in the Caithness, and but one inch longer than 

 in the Tasmanian Cachalot. 



In the following Table the individuals are arranged according to their presumed 

 ages, judging by the entire length of the skull. By comparing the figures showing the 

 proportions, it will be seen that, taking the length of the skull without the rostrum as 

 the basis of comparison, there is a relative increase in all the other dimensions during 

 growth, but that both in height and breadth, especially the former, this increase is com- 

 paratively slight and irregular, compared with the steady lengthening of the rostrum 

 which occurs as age advances. 



