46 EDWARD A. WILSON. 
In our own series the teeth of skull No. 1 are exceptionally strong and well- 
developed throughout, quite regular, and firmly rooted. The same remarks apply 
also to the teeth of ‘skull No. 14, but for the presence of a small additional incisor, 
and to those of No. 46. The incisor teeth of No. 25, however, are most unusual. 
They occur in two tiers, of which the outer four are the larger, and the inner four 
minute. Inskull No. 26 the teeth are all well developed but not well rooted. The 
alveoli are shallow, and just outside and behind the first premolar on each side of the 
lower jaw is what appears to be a persistent milk tooth. In skull No. 28 precisely 
the same apparent persistence of a milk tooth is to be seen in a similar position on 
each side of the upper jaw. 
In the fresh-killed animal it is quite a common thing to find all the cheek teeth 
loose, and when the skull is cleaned, they will be found in some cases to have no bony 
socket at all, being merely held in the fleshy gum ready to drop out sooner or later and 
leave no trace of their existence.* 
Ommatophoca has apparently the same range and distribution as Lobodon, and no 
doubt if both were dependent on the same food, there would be some struggle between 
them for subsistence. But seeing that Lobodon lives on crustaceans, and Ommatophoca 
mainly on cuttle-fish, and possibly some vegetable matter, there is obviously room for 
both, and it is not easy to see why in numbers Lolodon should be so very far ahead. 
If we consider the position which Ommatophoca has been given in the later 
classifications of the seals, we may doubt, I think, with some reason whether it has 
really as much in common with the Stenorhinchine as has been claimed for it, and 
whether it has not closer aftinities, notwithstanding the number of its incisors, with 
the Cystophorhine than with any of the Stenorhinchine. 
In all the seals, with but very few exceptions, the variation in the dentition is so 
excessive, that one is led to doubt the advisability of laying so much importance on 
this one feature. When one finds, for example, in the Phocine, grouped mainly upon 
the number of their incisors, first an example of Phoca vitulina with I. aoe 
3— 2 
variation of I. a ; then an example of Phoca fetida with I. =e as a variation of 
I a . then, too, in the Stenorhinchine, two examples of Monachus albiventer, one 
i 2 3-— 3 : 4—2 bogs 2—9 
with I. “——*, the other with I. , as variations of I. — =, and an example of 
o0 ee aaa 39 
Lobodon with I. eT as a variation of I. ye and no less than four variations 
* My attention has been drawn by Prof. F. Jeffrey Bell to the following discrepant statements concerning 
vestigial teeth in Whales. Prof. M. Weber (Die Saugetiere, 1904, p. 578) says of the Physetering :—“ Zahne des 
Oberkiefers rudimentar, brechen nicht durch”; but Bennett (Whaling Voy. Round the Globe, Vol. II., 1840, 
p. 168) says:—‘‘ The upper jaw is not altogether toothless, as usually described. On the contrary, it has on 
either side a short row of teeth, which, for the most part, are placed more interior than the depressions which 
receive the teeth of the lower jaw; though they sometimes, also, occupy the bottom of those cavities. Their 
entire length is three inches ; they are curved backwards, and elevated about half an inch above the soft parts, in 
which they are deeply imbedded, having only a slight attachment to the maxillary bone. In two instances, I have 
found their number to be eight on each side. They exist in both sexes of the Sperm Whale; and although 
visible externally only in the adult, they may be seen in the young animal upon removing the soft parts from the 
interior of the jaw.” 
as a 
