man can still do in an out-of-the-way part of the world to elucidate the
problems which await him.

The teeth of a crab-eating seal "are surmounted by perhaps the most
complicated arrangement of cusps found in any living mammal."[64] The
mouth is so arranged that the teeth of the upper jaw fit into those of
the lower, and "the cusps form a perfect sieve ... a hitherto
unparalleled function for the teeth of a mammal."[65] The food of this
seal consists mainly of Euphausiae, animals much like shrimps, which it
doubtless keeps in its mouth while it expels the water through its teeth,
like those whales which sift their food through their baleen plates."
This development of cusps in the teeth of the [crab-eating seal] is
probably a more perfect adaptation to this purpose than in any other
mammal, and has been produced at the cost of all usefulness in the teeth
as grinders. The grit, however, which forms a fairly constant part of the
contents of the stomach and intestines, serves, no doubt, to grind up the
shells of the crustaceans, and in this way the necessity for grinders is
completely obviated."[66]

The sea-leopard has a very formidable set of teeth suitable for his
carnivorous diet. The Weddell, living on fish, has a more simple group,
but these are liable to become very worn in old age, due to his habit of
gnawing out holes in the ice for himself, so graphically displayed on
Ponting's cinematograph. When he feels death approaching, the crab-eating
seal, never inclined to live in the company of more than a few of his
kind, becomes still more solitary. The Weddell seal will travel far up
the glaciers of South Victoria Land, and there we have found them lying
dead. But the crab-eating seal will wander even farther. He leaves the
pack. "Thirty miles from the sea-shore and 3000 feet above sea-level,
their carcases were found on quite a number of occasions, and it is hard