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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 2½ 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 3½ 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 Kaco, 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 cartloads; but after any ordinary gale a few specimens can be procured amongst the grass cast up by the highest waves. The animal, when touched, emits a quantity of violet-coloured fluid,
