SOME SNAILS OF THE OCEAN.
FROM COL. CHI. ACAD. SCIENCES.
Top row: Strombus puris dianae (Philippines). Bulla ampulla (Philippines). Harpa nobilis (Philippines). Second row: Littorina angulifera (United States). Fissurides listeri (United States). Third row: Nerita peloronta (Florida). Crepidula fornicata (United States). Terebra lamarckii (Sandwich Islands). Turbo petholatus (Indian Ocean). Fourth row: Nitra politificalis (Indian Ocean). Haliotis assimilis (California). Cerithalma aluco (East Indies).
There are three families of shells which are much sought after by conchologists, these are the top shells (Trochidæ), the turban shells (Turbinidæ) and the pheasant shells (Phasionellidæ). Altogether they embrace nearly five hundred species which live from the shore between tides to the lowest depths of the ocean. The shells of the top shells vary to a wonderful degree; some are large, others small; some are perfectly plain and smooth while others are ornamented by impressed lines, ribs and granules, some are very thin and delicate while others are large and massive. Many of the species are richly colored with brown, purple, black, green and yellowish, and all are more or less pearly. They are all vegetable eaters.
One of the best known is Trochus niloticus, a large, massive shell striped with brown, which is seen on the mantle of many households. One of the prettiest top shells is the ringed top shell (Calliostoma annulatum) found abundantly in some parts of California. The surface is marked by several rows of delicate points and the suture is bordered by a rich line of purple. It lives in the seaweed off shore and may be seen in pleasant weather crawling about among the weeds. During storms or rough weather this frail mollusk sinks to the bottom of the sea. The top shells inhabit many parts of the world, the coasts of Florida and California producing several very handsome and interesting species.
The Turban shells include many fine and large shells, a notable species being Turbo marmoratus, the “green turban” of the dealers. This shell is about seven inches in diameter, rich green outside and pearly inside. It is largely used for mother-of-pearl work and for making pearl buttons. It is said that the early Scandinavian monarchs used this shell as a drinking cup. At the present time it is used for ornamental purposes, richly mounted. In Japan the animal is used for making chop suey, being cut in little dice-like pieces.
The Pheasant shells are beautifully variegated with red, black, white and brown and are very interesting animals to study alive. When crawling, the left side of the foot moves forward while the right remains stationary, and when the right side moves the left remains stationary. This curious mode of progression has been likened to the canter of a horse. The larger species, with beautifully variegated shells, inhabit Australia, while the smaller species live in the Mediterranean Sea, South Africa, the West Indies and California.
The Neritas are very abundant in tropical and semi-tropical countries where they live on rocks and stones near low water mark. They are said to be nocturnal and spend the night feeding on seaweed. The shell of the Nerita is solid and heavy and variously ornamented with ribs, pustules and color patterns. The “bleeding tooth shell” (Nerita peloronta), so named from the presence of a red spot near one of the columella teeth, is a typical member of this genus. A species living in the Philippine Islands is said to climb trees to a considerable height.
The family Cerithiidae comprises some very handsome shells which inhabit salt, brackish and fresh water. They are found throughout the world but the finest species live in the tropics. The spire is very long and is composed of many whorls. Some shells are smooth and polished, while others are marked by frills, knobs, spines and ribs. The name Cerithium is from the Greek word ceration, meaning a small horn, and is used because of the horn-like shape of the shell. This family has its giants and also its pygmies, the latter being pretty, reticulated shells from one fourth to three fourths of an inch in length, living among the eel grass and other vegetation along the shore. There are over a hundred species of these small shells, and some when handled discharge a bright green fluid.
Whoever visits the seashore is bound to become intimately acquainted with the Littorinas, or periwinkles, for they cover the rocky shores everywhere, millions of their rounded shells clinging to the rocks when the tide goes out. They feed on the algae which grows on the shore. They are found in both brackish and fresh water. The common periwinkle (Littorina littorea) is extremely abundant on the shores of southern Europe and the northern part of the United States. In England it is used as an article of food and it is said that nearly two thousand tons are gathered annually and that a thousand persons are employed in capturing it. In London and other large cities they are sold on the street, the animal being picked out with a pin. It is used for bait in some of the fisheries and the oystermen plant many bushels on their oyster beds yearly to keep the seaweeds from accumulating. From these facts it will appear that this periwinkle is of considerable economic importance. All of the species are amphibious, living for a long time out of the water.