ll she lies as in a
boat, propelling herself by slowly sucking up water, and violently
ejecting it through a funnel, or syphon, at the same time using her arms
as oars, to increase her speed. Dame Nautilus can sink to the bottom of
the sea if she chooses; and when wishing to crawl about the sand or
rocks she turns over and carries her shell on her back, like a snail.

Beside the Nautilus is her little cousin, the Spirula peroni, which
sometimes, although not quite scientifically correct, is called an
Ammonite. Our Nautilus is frequently found alive, but only one living
specimen of this Ammonite has hitherto been caught, though several
shells have been obtained from different parts of the world with
portions of the fish attached.

Neither towing nets nor dredges have been successful in catching the
Ammonite, so it evidently does not live either on the surface or bottom
of the sea, but probably between the two, in deep water. The shell is in
a number of divisions, connected by a fine tube, and no doubt its use is
to regulate the depth at which the animal wishes to stay. This the
creature does by filling a number of the divisions with water or air,
according as it wishes to sink deeper or float upwards. After a gale, on
looking amongst the wrack cast up by the highest waves, large numbers of
our Spirula will be found. Light and fragile the shells are, and they
ride ashore without injury, and frequently are found covered with small
barnacles, a proof that many weeks must have elapsed between the death
of the owner and the casting ashore of its shell. In places in New
Zealand, and elsewhere, large fossil deposits of Spirula peroni occur.
It is worth remembering that, even though this shell is found as far
away as England, the only living specimen was caught on the New Zealand
coast. Our only other floating shells are three species of Janthina, or
violet shells, two of which are shown on Plate VII., Figures 1 and 2.

The first three shells on Plate II. belong to the Murex family. From
this species the ancient Tyrians obtained a portion of their celebrated
purple dye. The Janthina family (Plate VII.), however, contributed the
greater portion. The dye was extracted by bruising the smaller shells in
mortars.

~MUREX ZELANDICUS~ (Plate II.).--Fig. 1 is known as the spider shell, from
the spines, which look like spider's legs. It is a white or greyish
shell, about two inches in length. The long spines would interfere with
the