48 EDWARD A. WILSON. 
tion of the anterior nares, but in the relation of the anterior nares to the infra-orbital 
foramen, in the width of the orbits and interzygomatic regions; and in the small 
proportion of the ascending parts of the premaxille, which leave a large part 
of the anterior nares to be bounded by the superior maxilla. To these I would add 
that in Macrorhinus the premaxille make no effort to reach the nasal bones at all 
and leave the whole of the anterior nares to be bounded by the superior maxilla; in this 
respect very widely differing from the form of the same bones in the Stenorhinchine. 
It is of course true, as Captain Barrett Hamilton has pointed out, that in some 
respects the skulls of Ommatophoca and Cystophora differ. He allows, however, that the 
few characters to which he draws attention do not bring Ommatophoca any nearer to 
the Stenorhinchine, and this is just the point I wish to urge. The resemblance of the 
skull of Ommatophoca to that of Macrorhinus is seen to be very marked when only 
immature skulls of the latter are taken for comparison, a point which it is well to bear 
in mind when using such highly specialised animals for comparison as the adult Sea 
Elephant. It is exactly as one would expect that Ommatophoca, in which no very 
striking peculiarities have been developed, should find its closest resemblance in the 
young and immature skulls of Macrorhinus, which represent far better than the 
adults the more primitive type from which both of these seals as well as Cystophora 
have probably sprung. There appears, moreover, to be some reason for believing that 
Ommatophoca approaches Macrorhinus and Cystophora in the relative size of the sexes, 
at any rate to a greater extent than do the other members of the Stenorhinchine; and 
the evidence of all the fighting scars upon the adult males of Ommatophoca inflicted as 
they are, solely on the head and neck, as in the Cystophoring, and never on the body, 
as in the Stenorhinchine, affords strong support to the assumption that they fight 
standing up to one another on their fore limbs, as do the Cystophorine ; both Omma- 
tophoca and the Cystophorine approaching on this point far more closely to the 
Otarvidz than do any of the Stenorhinchine. 
In food also, as one would expect from the form of the teeth, Ommatophoca agrees 
with the Cystophorine, both members of which are said to live mainly upon 
cephalopods. There is also in the character of the hair of Ommatophoca a certain 
similarity with that of Macrorhinus, both having short, flat, broad and decidedly 
coarser hair than occurs in any of the Stenorhinchine. 
There is, as I have said, a strong general similarity in the form of the hind 
flippers of these two seals, a similarity which is not shared by other members of the 
Stenorhinching, and the extremely rudimentary nature of the claws upon the hind 
limbs is characteristic of both, as also of Monachus, and different from those of 
Stenorhinchus, Leptonychotes, and Lobodon, in all of which the claws are well developed. 
In the fore limbs, however, Ommatophoca stands apart with claws as rudimentary 
as those upon its hind limb, whereas the claws of the fore limb in Macrorhinus and 
Monachus and of both limbs in Cystophora and Halicherus are exceptionally well 
developed. 
