CALLIOSTOMA PELLUCIDUM (Plate VI.).—Fig. 3 (late Zizyphinus selectus) is a whitish shell, covered with chestnut-coloured spots and splashes. It is about 1-1/2 inches across.
CALLIOSTOMA PUNCTULATUM (Plate VI.).—Fig. 4 (late Zizyphinus punctulatus) is the commonest and least fragile of this family. It is seldom more than 1-1/4 inches across. Its rounded whorls, and prominent chestnut and white granules, make it easily distinguishable.
TROCHUS VIRIDIS (Plate VI.).—Fig. 5 is a greenish, cone-shaped shell. The interior is nacreous, and the exterior covered with coarse granules. The base, which is flat, is greyish. The figure but faintly shows the contour of this shell, which is a perfect cone. The young differ somewhat from the adult shells, and have a bright pink tip to the spire. In the plate the upper shell is a young one, and the two lower are adults. They are found amongst rocks at low water mark, in harbours, as well as in the surf. It is very difficult to extract the animal from the shell. Its maximum size is one inch across.
TROCHUS TIARATUS (Plate VI.).—Fig. 6 is usually white, with large grey or brownish-purple dots and bands on both the upper surface and the base, but it is a very variable shell. It is seldom as much as half an inch in length, and has a nacreous interior. It is covered with fine granules, and the base is flat. It appears to live slightly below low water mark, and can be easily obtained by dredging in harbours. The cup-shaped hollow at the base of the spire is much more pronounced than in the Viridis.
There is another not shown on the plate, the Trochus chathamensis, a small white shell, with pink or brownish-purple markings, that hitherto has only been found in the Chatham Islands.
ETHALIA ZELANDICA (Plate VI.).—Fig. 7 (late Rotella zelandica) is a well-polished, smooth shell, washed up in large numbers on the ocean beaches. The colours of the upper side vary, but are usually chestnut or purple waving lines on a yellowish-white ground. On the base is a circular band of purple round the columella, which is white. The interior is nacreous. Occasionally a shell is entirely pink, and then the circular band on the base is pink also. The largest shell I have seen was nearly one inch across, and, being very flat, would be only half an inch high. They appear to live in sandy ground, below low water mark in the ocean; and a dredge if drawn over one of their favourite spots will be filled with them. I have dredged half a bucketful at one cast between Karewa and Tauranga in five fathoms of water. The former name was Rotella zealandica, and Rotella, meaning a little wheel, well described the appearance of the shell, the waving line representing the spokes.
NATICA ZELANDICA (Plate VI.).—Fig. 8, a yellowish or reddish-brown shell, with chestnut-brown bands, the interior being pale brown, the mouth and its vicinity white. It is a clean, bright little shell, upwards of an inch across. Those in the ocean are lighter in colour, and larger and more solid than those found in harbours. As the tide falls in harbours, they conceal themselves near low water mark, especially in the vicinity of marine grass banks. When the tide is rising on a warm, sunny day, they spring out of the sand, dropping sometimes two or three inches from where they had been concealed. The operculum is horny, with a shelly outer layer; and the animal is prettily mottled and striped red and white.
There are two other Natica found in New Zealand, neither of which exceeds one-third of an inch across, and in shape are very like the N. zelandica. The Natica australis is a brown or grey shell, and the Natica vitrea is white.
NERITA NIGRA (Plate VI.).—Fig. 9 (late Nerita saturata) is a heavy, solid blue-black shell, with a whitish interior. This sombre-looking member of a handsome tropical family (of which the bleeding tooth Nerita is the best known) is sometimes over an inch in length, and found in large numbers clinging to the surf-beaten rocks of the North Island, quite up to high water mark. The operculum is shelly and prettily mottled with purple. This shell will stand boiling water, and, in fact, boiling water is required to kill the animal, which is quite as tenacious of life as an oyster. The Maori name is Mata ngarahu.
AMPHIBOLA CRENATA (Plate VI.).—Fig. 10 (the New Zealand winkle), lately known as Amphibola avellana, is an uneven, battered-looking shell of a mixed brown and purple colour, the interior being purple and the mouth whitish. It is an inch or more in length. Most mud flats up to high water mark are strewn with Amphibola. The natives eat this shellfish, which they call Titiko or Koriakai, in large numbers; but the muddy flavour, according to our ideas, makes it unpalatable.