The Single British species (H. tuberculata) is not actually found on the English coast, but common on rocks and stones at low-water in the Channel Islands. It is frequently eaten by the poor of those islands and the north of France; other species in New Zealand, China, Japan, West Africa, and elsewhere, constitute a common article of diet among the natives. Haliotis-shells are largely used in the manufacture of pearl ornaments, and in all kinds of inlaid work.
Fig. 6.
Top-shell (Turbo petholatus). (From the Indo-Pacific Ocean.)
a. Inner surface of operculum. b. Exterior of ditto.
Cases 12–18.
The Trochidæ, and Turbinidæ are two extensive families, the animals of which are very much alike, and mainly distinguished by the operculum, which in the former is horny, and shelly in the latter. The shells of these families are beautifully pearly within, and the external shelly coat is generally brightly coloured and highly ornamented. Several very pretty species are found on our own shores. The opercula of Turbo petholatus (Fig. 6), from the Indian and Pacific Oceans, are frequently mounted in gold and silver as scarf-pins, ear-rings, &c.
Cases 18–20.
The Nerites are mostly found in tropical countries, and, like the Winkles, are very strongly made, to resist the force of the breaking waves. The Neritinas are partly found in the sea, and partly in fresh water, and are less solid shells. The third section of Neritidæ, the Septariæ, are shaped very much like Limpets, except that the apex is at one end instead of central. They are, however, very different animals, and furnished with a shelly operculum imbedded in the foot.
Order 2.—Pectinibranchia.
Cases 22–94.
In most cases the molluscs of this order have an attached monopectinate gill and a single osphradium. A few are fresh or brackish water forms, but the majority are marine.