in form, the
caudal vertebrae running through the middle of it. The immense
muscular power of this tail, with its broad flanges, arises from the
flesh of the body, terminating in long cords of tendon, running to
the tip. The vertebral column is often ankylosed in the fore-part,
but is extremely elastic, owing to the cartilaginous cushion between
each bone in the latter half. Thus, whilst the fore-part is rigid,
the hinder is flexible in the extreme. The brain is large and much
convoluted; the heart is very large, and the blood-vessels extremely
full and numerous, with extensive ramifications, which, being filled
with oxygenated blood, assist in supporting life whilst submerged.
The lungs are also very large. The laryngeal and nasal passages are
peculiar. The following description is by Dr. Murie: "In front of
the larynx of man we all know that there is an elastic lid, the
epiglottis, which folds over and protects the air passage as food
is swallowed. The side cartilages constitute the walls of the organ
of voice and protect the vocal chords. Now, in the comparatively
voiceless whale, the cartilages, including the epiglottis, form a
long rigid cylindrical tube, which is thrust up the passage at the
back of the palate in continuity with the blow-hole. It is there held
in place by a muscular ring. With the larynx thus retained bolt
upright, and the blow-hole being meanwhile compressed or closed, the
cetacean is enabled to swallow food under water without the latter
entering the lungs." The stomach is peculiar, being composed of
several sacs or chambers with narrow passages between; the
intestines are long, glandular and, according to Dr. Murie, full of
little pouches. There is no gall bladder; the gullet is very narrow
in some and wider in others. Some have teeth, others are without.
The eyes are small; the ears deficient externally, though the
interior small ear-bones of ordinary mammals are in these massive
and exceedingly dense, so much so, as Murie observes, as to be
frequently preserved fossil when other osseous structures are
destroyed.

The cetacea have been divided into the _Denticete_, or Toothed Whales,
and the _Mysticete_, or Whalebone Whales. The former contains the
river dolphins, the ziphoid whales, the gigantic sperm whale, the
sea dolphins, and the narwhal or sea unicorn. The latter contains
the baleen whales.

_DENTICETE--THE TOOTHED WHALES_.

None of the larger species are found on these coasts, o