while the interior is iridescent. It is found on rocks in the 
open sea in both Islands, but is a rare shell. The operculum is 
white and shelly. 
TURBO HELICINUS (Plate VI.).—Figs. 16 and 17 (late 
Turbo smaragdus) is a blackish-green shell, found in great numbers 
at half tide mark on rocks all over New Zealand, especially at 
the entrance to harbours and in sheltered bays. Some are as 
much as 23 inches across. The inside is white and glistening. 
The operculum is a solid, round, shelly one, with a greenish 
centre. In some specimens the outer side of the whorl, instead 
of being round and smooth, has two or three prominent raised 
ribs or bands on it. This variety is called Tricostata, and is 
represented by Fig. 16. I am inclined to believe it is only the 
young form of the ordinary variety. The Maori name is Ata 
marama. 
ASTRALIUM SULCATUM (Plate VI.).—Fig. 18 (late 
Cookia sulcata) is a pinkish-brown shell, sometimes over 34 inches 
wide. The interior is pearly, and the operculum is shelly, solid, 
and white. The laminae which cover the shell are easily bleached 
off, and when the shell is cleaned it has a handsome appearance. 
It is found in considerable numbers at low water mark amongst 
rocks on exposed beaches all over the North Island. The Maori 
name is Kakara or Kaeo, both of which names are also given 
to the Purpura haustrum (Plate II., Fig. 11). 
ASTRALIUM HELIOTROPIUM (Plate VI.).—Fig. 19 is 
generally known as the circular-saw shell, and, although found 
all over New Zealand, is comparatively rare. It is reddish-purple, 
with an iridescent interior, and is sometimes over four inches 
in width. The shells on the plate are adults. The spines of the 
younger shells are much longer than those of adults. The best 
specimens have been dredged by oyster boats. 
Plate VII.—Figs. 1 and 2 are Janthina, or violet shells, 
representatives of which are found all over the warmer parts of 
the world. The Janthinae live in great numbers on the surface 
of the ocean, being unable to sink, and are swept by gales and 
currents in every direction. At intervals, after very heavy gales, 
they come ashore in the Northern part of New Zealand in cart- 
loads; but after any ordinary gale a few specimens can be pro- 
cured amongst the grass cast up by the highest waves. The 
animal, when touched, emits a quantity of violet-coloured fluid, 
