ly formed out of the mouth: this is a peculiarity of a new
Antarctic genus found first on the Discovery. It has the most complex
water-tubes, which it uses as legs, and a few limy rods in its soft skin
instead of the bony calcareous plates of sea-urchins and starfish. After
them came the feather-stars, a relic of the old crinoids which used to
flourish in the carboniferous period, examples of which can be found in
the Derbyshire limestone; and there were thousands of brittle-stars, like
beautiful wheels of which the hubs and spokes remained, but not the
circumference. These spokes or legs are muscular, sensory and locomotive;
they differ from the starfishes in that they have no digestive glands in
their legs, and from the feather-stars in that they do not use their legs
to waft food into their mouths. Once upon a time they had a stalk and
were anchored to a rock, and there are still very rare old stalked
echinoderms living in the sea. This apparently geological thing was found
by Wyville Thomson in 1868 still living in the seas to the north of
Scotland, and this find started the Challenger Expedition for deep-sea
soundings in 1872. But the Challenger brought back little in this line.
Most of the species we found were peculiar to the Antarctic.

There were Polychaete worms by the hundred, showing the protrusable
mouth, which is shoved into the mud and then brought back into the body,
and the bristles on the highly developed projections which act as legs,
by which they get about the mud. These beasts have apparently given rise
to the Arthropods. In a modified and later form they had taken to living
in a tube, both for protection and because they found that they could not
go through the mud, which had become too viscous for them. So they stand
up in a tube and collect the sediment which is falling by means of
tentacles. They spread from one locality to another by going through a
plankton embryonic stage in their youth. They may be compared to the
mason worms, which also build tubes.

But as Lillie squatted on the poop surrounded by an inner ring of jars
and tangled masses of the catch, and an outer ring of curious scientists,
pseudo-scientists and seamen, no find pleased him so much as the frequent
discovery of pieces of Cephalodiscus rarus, of which even now there are
but some four jars full in the world. It is as interesting as it is
uncommon, for its ancestor was a link between the vertebrates and
invertebrates, though