PSEUDORCA CRASSIDENS. 
199 
griseus are not so broad as those of the ca’ing-whales, (nay not even so broad as those of our 
crassidens) ; but judging by the figures, 1 this dolphin seems, nevertheless, as far as the rest of 
the beak is concerned, to be much more similar to these Cetaceans, than to the type of any other 
species. But the case is somewhat different in the species which we are here describing, the 
surface of the beak is from its origin somewhat convex, the dental row occupies almost the whole 
length of the beak, the superior maxillaries have still a considerable thickness, in order to 
leave room for the very deep sockets of the teeth, and are, generally speaking, much more like 
the same bones of an Orca than those of the ca’ing-whale or the Grampus. 
The asymmetry pervading the whole cranium also affects the intermaxillaries, and 
especially the hindmost part of these bones. The right one is perceptibly broader than 
the left, and is quite contiguous with the corresponding nasal bone, its posterior extremity 
inserting itself between the latter and the superior maxillary; the left, on the contrary, does not 
extend quite so far backwards, and more especially does not quite reach the nasal bone, which is 
also influenced by the general asymmetry, being considerably smaller than the right one. Just 
before the nostrils there is a notch in the inner edge of both of the intermaxillaries, and in the 
space thus left a portion of the superior maxillaries become visible. In conformity with the 
general obliquity of the head the visible part of the right superior maxillary is always 
somewhat larger than that of the left; but the portion of these bones, laid bare in this 
manner, may, in different individuals, be sometimes a little larger, sometimes a little smaller. 
Something very similar also takes place in the common ca’ing-whale, and (though in a smaller 
degree) in the northern killers, and various other dolphins, amongst others in the common 
porpoise. On the contrary, it does not seem to be the case with Grampus griseus, to judge by 
Cuvier’s figures, and from this Cetacean the dolphin here described also differs in another and 
more important respect, as far as this part of the skull is concerned. The intermaxillaries of 
Grampus griseus are dilated in front of the nostrils, according to the statements of both Cuvier 2 and 
J. E. Gray, 3 so as to cause a convexity in this place; but no trace of anything of the kind is to 
be found in our species, in which the intermaxillaries are, on the contrary, somewhat depressed at 
some distance before the nostrils, and the distinctly defined three-cornered region in this place, 
denominated by Gray the “ triangle,” here forms a slight depression, as in most other 
dolphins. 
As far as may be inferred from Owen’s short description and small figures of his Phocana 
crassidens, it must be quite similar to our dolphin, as to all the details of the characters 
of the cranium which have been examined above; it has, therefore, hitherto been unnecessary 
to refer particularly to the fossil form, and compare it with our specimens. We shall 
now mention the only point, as to which the resemblance may at first glance seem doubtful, 
and which accordingly must be considered more minutely. We know that in the dolphins the 
vomer is sometimes visible on the inferior surface of the beak (sometimes even in two different 
places), and thus it may have some share in forming the palatine surface; sometimes on the 
contrary, it does not appear there at all. Now Owen states that the vomer appears on the 
1 ‘ Reclierches s. 1. Oss. Foss.,’ 4-rne ed. Atlas, tome deuxieme, pi. 223, figs. 1 and 2. 
2 Ibid., 4me ed. tome 8, 2me partie, p. 125. 
5 'The Zoology of the Voyage of H.M.S. Erebus and Terror/ “ Mammalia/’ p. 30. Catalogue of 
the Mamm. in the Coll, of the Brit. Mus., P. 1, Cetacea, p. 82. 
