MaDimalia, 51 



lis to discover the relationships of this strange form, but are as 

 distinct from any other genus of Stenorhynchinae as each of them is 

 in this respect from the rest. 



Altogether, I can only regard Oinmatoplioca as a most interesting 

 generalised form, an annectant genus, showing affinity ])oth to the 

 Stcnorhynchinac and the Cijstophorinae, to both of wliicli it stands in 

 a, (piasi-ancestral relationship. I think it more convenient that it 

 should remain included in the Stenorlnjnchinae than tliat it should 

 form the type of a new family or sulj-family. 



To come to individual differences (apart from the teeth) I find 

 little variation in the eight skulls before me. The most variable 

 character in the cranium appears to be the amount of the superior 

 maxillae which enters into the boundary of the superior nares. The 

 length of this section of the boundary varies in the different specimens 

 from 5 to 17 millimetres. 



As in Lohodon and LeiHonycliotcs there is practically no develop- 

 ment of the sagittal crest. The lambdoid crest is, however, well 

 developed. 



Sex. — The sex of Eoss's specimens is unknown. One skull of 

 those collected by the ' Bclyica ' was that of an adult female, the other 

 that of a young male. Since one of the known females is the largest 

 skull of the four and there are no apparent differences in the size 

 of the teeth, I see no way of telling the sex of the two unknown 

 skulls. Neither can the one unknown female amongst the skulls 

 brought home by the ' Soutkern Cross ' be certainly indicated — unless, 

 indeed, it be No. 1, which, although distinctly adult, is the smallest 

 skull of the eight known. All things considered, it is evident that 

 there can be no striking differences between the sexes of this Seal, 

 and it is as likely as not that differences of size represent age and 

 not sex. 



Aye. — There is little to be said on this point. In many of the 

 skulls, even the larger examples, the teeth are fresh or but slightly 

 worn. Yet, in the smallest skull of all (No. 1 of the ' Southern Cross ' 

 collection) not only have the cheek-teeth completely disappeared 

 from both jaws, but in some cases hardly a trace of the alveoli is 

 discernible. 



Dentition. — Undoubtedly a great deal of the interest aroused by 

 OmmatojjJuxM centres in its dentition. The first striking point in 

 this connection is the remarkable feebleness of the teeth. Thus, with 

 a skull attaining to more than double the size of that of Phoca 

 yroenlandica or P. vitulina, the teeth are about equal in size to 

 those of the former, and actually inferior to those of the latter 



E 2 



