1881.] 



PROF. W. H. FLOWER ON THE ELEPHANT SEAL. 



161 



lopment of the canine teeth, as can he well seen in the figures of the 

 type skull of the female M. anc/ustirostris, as given by Allen. On 

 comparing the upper surface of this with a series of male skulls, it 

 will be seen that the difference consists chiefly in the extent to which 

 themaxillse project beyond the sides of the praemaxillse, which in the 

 former is almost nil, and in the latter very considerable, to allow 

 room for the roots of the great canines on each side of the prseniaxilhe. 

 Even in the youngest skulls this difference in the sexes is seen. 

 The variations in the proportion of the breadth of the rostrum 

 measured at the middle, halfway between the nasal orifices and the 

 ends of the prsemaxillse, in different specimens, are shown in the fol- 

 lowing table : — 



There is certainly one character by which the type specimen of 

 M. angustirostris, judging from Gill's description and Allen's figure, 

 differs from any of the skulls of southern Elephant Seals with 

 which I have compared it. This is the shorter antero-posterior 

 extent of the palate-bones, and the deeper emargination of their 

 hinder border. Before this distinction can be accepted as a specific 

 character, it should be known whether it is constant. There is 

 much variation in the size of the palate-bones of the southern forms : 

 the length from before backwards between the palato-maxillary 

 suture in the middle line and the spine in the large skull No. 3921 

 is but 35 millims. ; in the somewhat smaller skull. No. 3920, the 

 same distance is as much as 51 millims.; and in the largest skull 

 (No. 3921a) it is 65 millims., therefore about double that of the 

 skull which comes nearest to it in general size. 



When the idea prevailed that each species was separately created 

 in the region which it inhabits, geographical reasons were stronger 

 than now for assigning specific distinction. But Allen fully admits, 

 indeed suggests himself, that the two presumed species, though long 

 isolated, have been derived from one stock, "the southern beiug an 



Proc. Zool. Soc— 1881, No. XI. U 



