216 THE ANTARCTIC MANUAL. 
tion, possibilities of the rise of what now appear to be homogeneous 
orders of mammalia independently and in different regions, just as 
Dr. Kiikenthal believes has been the case in regard to the whalebone 
ang toothed whales. 
In the whole zoology of the Antarctic Phocide nothing can be 
more remarkable than the divergencies in the shape and size of the 
cheek teeth. Side by side on the South Polar pack-ice occur four 
genera, Lobodon, Ogmorhinus, Ommatophoca and Leptonychotes. Living 
the same life, with the same sources of food around them, and more- 
over, armed with the same number of teeth, no two agree in any 
single respect in the form and pattern of the individual grinders. In 
Ogmorhinus there is found the most formidable, in Ommatophoca the 
most feeble dentition of the family; yet the feeble development of 
the teeth is in the latter supported by a lamdoid crest far exceeding 
that of Lobodon or Leptonychotes. Again, while Lobodon seems to find 
necessary for its existence a set of teeth surmounted by perhaps the 
most complicated arrangement of cusps found in any living mammal, 
Leptonychotes survives on the same ice-berg with the help of a simple, 
fairly strong dentition. Lastly, while there is, so far as is known, 
little individual variation in the three remaining genera, in Ommato- 
phoca there occurs one of the most remarkable instances of individual 
variation in mammalian teeth known to science. Not only are the 
size and the number of the roots of each tooth variable, but the 
actual number of teeth in any particular specimen can never be fore- 
told with certainty. 
Few things can be more certain than that such a state of things 
as I have here described cannot be meaningless. Developments like 
these must in each case be connected with habits and food, which 
must surely differ in a manner corresponding to such remarkable 
differences of structure. This supposition is, I think, supported by 
the fact that, as already stated, there are to be found amongst the 
Antarctic Phocide resemblances of dentition to those of Northern 
seas. Thus it might be suspected that the resemblances between the 
teeth of Ogmorhinus and of Phoca hispida is not altogether without 
reference to similar uses. 
With a view to approach the root of this matter I have examined 
with some care all the available accounts of the habits of the Ant- 
arctic Phocidw. Meagre as these are there is enough in them to afford 
me some assistance, especially in the writings of Monsieur Racovitza. 
Thus the fact that Oymorhinus is alone described as at least occasion- 
ally killing and eating penguins, and that it accepted as food the 
bodies of two of these birds thrown overboard from the Belgica, is 
