54 Soiif/icni Cross. 



inc»Iur. .us su wrll parallclcl in Oiniiwtophnca in the case of the last 

 iwo lui.hirs. K(.r in n ir of tlic instances «.f sujiposed reduplica- 



lion ..f ni. ' arc either ol the " daughter " teeth so well formed or 



nK»ted na llie remainder of the series. 



This process of roihiction is admirably in keeping with the 

 anatomy of an animal whose teeth are I'eeble, jaws short, and whose 

 prey RMiuires neitlier hokling nor much mastication. 



Further, the fact that, except in the case of No. 3245, the supposed 



cases of rcihiplication were in each case in connection with m. -- and 



never in the Uiwer 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 



n III ■* ^ "^ ,n. " ^ " . Nor could we indeed attempt to do so were 

 '■'4x4' 1x1 



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 



([uestions of the present kind. It seems to be a skull in which both 



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



2 1 



regaixl 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 Ommatoijhoca as having 

 »>rigiually 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 

 forinati(jn of a new family for the sole reception of Ommatojjhoca. 



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

 AA luis lieen shown by Professor Nehring. No other species 

 of Pkrless Se;d jK)Ssesses a similar dental formula, l)ut Omma- 

 tuphiKti is just that cranially generalised species in which we 

 should exj)ect such a type of dentition to occur — a dentition which, 

 perhaps, suggests an interesting bridge between the Phocidae and 

 Strnorhijiwhimu-. 



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 wholesiile process of this kind. As to the former matter, the 

 exari niusf.s of such reduplication hardly lend themselves to 



