ke a small spade, and walk along a sandy beach
at low water. As the tide begins to rise, and the buried shellfish feel
the water, he will see the sand moving, or showing signs of life; and if
he digs quickly enough he may unearth rare and beautiful specimens for
his cabinet.

Wherever animals or vegetables are crowded, disease appears. This is
true of molluscs, and it is seldom worth while looking for a specimen
fit for a collection where any particular kind of shellfish lives in
great numbers. Animal and vegetable parasites will be found wherever
shellfish are crowded together. For instance, a perfect cockle, or one
good enough for a collection, will not be found on a cockle bank, but
solitary ones must be looked for elsewhere.

[Illustration]

CHAPTER III.

DESCRIPTION OF PLATES.

Amongst the best known shells in any part of the world the Nautilus
takes a leading position. Named Argonauta by scientific men, after the
Argonautae, or sailors of the Argo, it has been the subject of many
legends from the earliest times. Aristotle describes it as floating on
the surface of the sea in fine weather, and holding out its sail-shaped
arms to the breeze. This is now known to be incorrect, as the use it
makes of these arms is to help it in swimming through the water. New
Zealand's specimen, the Argonauta nodosa, also known as Argonauta argo,
the most beautiful of the four known species, is depicted on Plate I.
Being a floating shell, and found even hundreds of miles from land, our
Nautilus is not peculiar to New Zealand. Its beautiful white,
horny-looking shell can be obtained from most parts of the Pacific and
Indian Oceans, but in no part of the world can finer specimens than ours
be found. It is known to the Maoris as Muheke or Ngu, and colloquially
as the Paper Nautilus.

The animal that produces this shell belongs to the octopus, or
cuttlefish, family. The male is an insignificant-looking octopus, about
an inch long. The female grows many times larger, as can be imagined
from a glance at the shell in the plate, which measured nine inches
across, and was found at Mayor Island, in the Bay of Plenty, and is now
in the possession of Mr. C. Spencer.

In the shell the female lays her eggs, and in it the young are hatched.
Unlike all other shells, the Nautilus is not moulded on the animal, nor
is she even attached to her shell by muscles. When washed ashore she can
wriggle out of her shell and swim away. In her she