64 Southern Cross. 



molar, as so well paralleled in Omnwtoplioca in the case of the last 

 two molars. For in no one of the instances of supposed reduplica- 

 tion of m. — are either of the " daughter " teeth so well formed or 



rooted as the remainder of the series. 



This process of reduction is admirably in keeping with the 

 anatomy of an animal whose teeth are feeble, jaws short, and whose 

 prey requires neither holding nor much mastication. 



Further, the fact that, except in the case of No. 324&, the supposed 



cases of reduplication were in each case in connection with m. — and 



never in the lower jaw, does not point to a meaningless reduplication 



of any tooth of the series. 



Lastly, it seems hardly advisable or possible to take as 



normal any condition other than that of the majority, in this case 



4x4 2x2 



p.m. ,, m. -. Nor could we indeed attempt to do so were 



^4x41x1 



it not for the existence of No. 324/^. This skull is undoubtedly the 



most curious of the whole series. I look on it as one of those quite 



abnormal specimens which must in all cases be eliminated from 



questions of the present kind. It seems to be a skull in which both 



reduction and reduplication of the teeth have occurred — the former in 



2 1 



regard to m. — , the latter in regard to p.m. — . 



I believe, then, that until the accumulation of more specimens 

 proves the contrary, we must regard Ommatoplioca as having 

 originally possessed two upper molars, one of which it is now in 

 process of losing — a supposition which, if borne out, may have far- 

 reaching results, and may even turn the scale in favour of the 

 formation of a new family for the sole reception of Ommato^yhoca. 



A distinct parallel to such a state of things occurs in Halichoerus, 

 as has been shown by Professor Nehring. No otlier species 

 of Earless Seal possesses a similar dental formula, l)ut Omma- 

 toplioca is just tliat cranially generalised species in which we 

 should expect such a type of dentition to occur — a dentition which, 

 perhaps, suggests an interesting bridge between the Phoddae and 

 Stenorhynchinac. 



In my previous remarks I have not attempted to discuss the 

 causes of reduplication in teeth, nor alluded to those hypotheses 

 which view with favour the rise of the Cetacean dentition by means 

 of a wholesale process of this kind. As to the former matter, the 

 exact causes of such reduplication hardly lend themselves to 



