is that the whale completely empties the
gas out of its lungs by muscular compression of the body-wall before
diving, so that there is no gas left in the body to be acted on by the
increased pressure resulting from its sinking into deep water. I am
unable to deal with this puzzle myself, and I have not been able to
find any naturalist or physiologist who can throw light on the matter.

The toothed whales are nearer to the ancestral primitive whales than
are the whalebone whales. The latter are the more peculiar, and
specially adapted with their huge heads and mouths (a third the length
of the whole animal in the Greenland whale), and their palisades of
350 whalebone planks, some 12 ft. long, on each side of the mouth. I
may mention in parenthesis that, whilst whalebone has been largely
superseded by light steel in the making of umbrellas and corsets, its
value remains, or rather increases, on account of its being the only
material for making certain kinds of large brushes which are used in
cleaning machinery. The whalebone whales have, when first born, very
minute teeth hidden in their jaws; they disappear. Some of the toothed
whales have teeth only in the lower jaw (the cachalot), others (the
beaked whales, Ziphius, etc.) have only one pair or two pairs of
teeth. These are tusk-like, and placed in the lower jaw. Others (the
dolphins and porpoises) have very numerous peg-like teeth in each jaw.
Some of them feed on fish, pursuing the shoals of fish in parties or
"schools."

A truly terrible toothed whale is the large porpoise called the killer
(known to zoologists as _Orca gladiator_). He is the wolf of the sea,
far more active and formidable than any shark, about 10 ft. long, and
strangely marked in black, white, and yellow. He has jaws bigger than
those of the largest Mugger crocodile, and a tremendous array of
fang-like teeth. These killers hunt the Right (or whalebone) whales in
all parts of the world, in parties of three to twelve. They hang on to
the lips of their enormous "quarry," and once they get a hold, in
twenty minutes tear it into pieces. Often they satisfy themselves with
tearing out and devouring the gigantic tongue of their victim, leaving
the carcase untouched.

The narwhal and the white whale, or Beluga, which furnishes
"porpoise-hide" for boots and laces, are both caught in northern seas,
and form a closely allied pair, similar to one another in shape and
colour (the one white, the other grey), a