34 Southern Cross. 



investigations, it is unsafe to attempt to guess the sex of any skull 

 of this Seal. 



Whether, however, the larger skulls be those of males or of 

 females, there are, as in the case of Lobodon, so many specimens of 

 intermediate proportions that the determination of the sex they 

 represent must always be a matter of difficulty. It can only be 

 supposed that, as in the case of the male of Otalgia ursina and 

 0. jnhata, the size and development of the larger sex of the Leopard 

 Seal are exceedingly variable characters. 



Age. — As might have been expected, the cheek-teeth of this 

 species show, in a far more marked degree than those of the other 

 three Antarctic Seals, the effects of use and wear. But although 

 there is a very great difference between the clean and unworn teeth 

 of some specimens, and the worn teeth of others, it is strange that 

 those of the largest specimens which I have examined are clean 

 and unworn. In young individuals the cheek-teeth are much 

 crowded. 



In some specimens the sagittal crest is prominently developed : 

 the largest which I have measured reached a height of twelve milli- 

 metres. In all the lambdoid crest is large. 



Individual variation. — Conspicuous individual variations in the 

 skulls of this species seem to be rare. It may be worth placing on 

 record that the posterior margin of the palate of No. 325c? of the 

 British Museum Collection is formed as a crescent and not as 

 a Y as in all the other specimens. This variation is said to be 

 paralleled in the case of a single specimen (No. 1095), which 

 forms part of the collection in the Eoyal College of Surgeons of 

 London. 



Teeth.— T\\Q massive teeth and prominent crests at once stamp 

 the Leopard-Seal as distinct from the other three Antarctic species, 

 and demonstrate, as I have already argued, that the dentition is 

 adapted to a different kind of food. 



Skeleton.— ThQ skeleton has been fully described by Sir William 

 Turner, who used it for comparison in his detailed description of that 

 of Lcptonychotcs (see Table II, pp. 32, 33). 



