46 



the forehead separates the two unequal cavities, is formed by the 

 base of the left maxillary and the base of the right intermaxillary, 

 which both meet at the summit of the head. The right inter- 

 maxillary, however, does not join the occipital, but is separated 

 from it by a thin. edge of the right maxillary, so that the occipital 

 is doubled in front by the base of the maxillai-ies alone ; in this 

 way the left intermaxillary is much shorter than the right one, 

 and mounts no higher than the wall of the left nostril, which it 

 partly forms. It is the enormous width given to this left nostril 

 that thus distorts the bones. The vomer forms wdth the sides of 

 the intermaxillaries a broad hollow canal, in the middle of which 

 it tapers away to a point which divides that intermaxillary 

 emargiuation which terminates the broad snout. 



The nostrils are pierced in the middle of the upper surface of 

 the head, not, perhaps, so obliquely as in the genus Gatodon : 

 but they are here much more unequal in size, one being more 

 than ten times the size of the other. The nasal bones are in this 

 manner thrown completely out of their j)lace. The right one is 

 a very small triangle, at the base of the ethmoidal, which forms, 

 with the right intermaxillary, the wall of the small right nostril. 

 It also forms the lower edge of the dividing ridge, and terminates 

 abruptly and perpendicularly above the base of the vomer. The 

 left nasal bone is more than two inches long, and somewhat of a 

 parallelogram in shape. With the left intermaxillary, the left 

 maxillary and the ethmoid together, it forms the wall of the 

 enormous left nostril. 



In this animal, as we have said, the two massive maxillaries 

 touch each other behind where they are doubled by the occipital, 

 and leave no part of the frontal visible. A notion of their heavy 

 proportions may be obtained from the fact, that a section of the 

 right maxillary, taken through the right nostril, perpendicular to 

 the medial line of the head, would be a triangle, having four 

 inches and a half for its base, and about one inch and a half for 

 its height. 



Of all the orders of Mammalia the structure of the skull 

 varies most in the Pacliydermata and Cetacea ; indeed the skull of 



