THE TURBAN SHELLS AND STAR SHELLS - FAMILY TURBINIDAE Shell spiral, turban-shaped, solid, with simple circular or oval aperture; operculum calcareous, heavy, convex outside, with thin,flat, spiral,horny layer on inner face, nucleus not central. Body with oval foot, square in front, bearing cirrhi along sides; head bears a veil between the two long tentacles, with two eyes on short stalks at their outer bases; radula well developed; food vegetable; habitat, shores of warm oceans. A large family of several genera, chiefly distinguished from the Trochidm by the calcareous nature of the thick operculum, and by its few coils.
Genus TURBO, Linn.
Shell turban-shaped, usually large, heavy; whorls rounded; aperture nearly round, more or less drawn out at base; operculum circular, flat or concave inside.
The Green Snail (T. marmoratus, Linn.) of the curio-dealer and collector, is the giant of the family of turban shells. It has the characteristic turban shape with the spire somewhat de pressed, and the whorls few, square-shouldered and knobbed, the body whorl much larger than the others. The largest shells are eight inches in height and diameter. The columellar region is excavated considerably; there is no umbilicus.
As an ornament for shell cabinets and mantelpieces these "green snails" are familiar to many. In Scandinavia the mon archs have from the earliest times had these shells mounted in silver and studded with gems for royal drinking cups. They 209 The Turban Shells and Star Shells• are not actually used as such nowadays, but kept in cabinets in deference to old usage. The Japanese cut up the soft parts of this species and use it for making chop suey. The thick, pearly substance of the shells is cut into buttons and ornaments.
Habitat.—Indian Ocean, Philippines, Japan Sea.
The genus Turbo is divided into several sub-genera, based upon differences of the radula and operculum.
Sub-genus SARMATICUS, Gray Shell depressed, much broadened at base, with oblique long aperture and broad columella. Operculum beset outside with club-shaped processes, inside flat.
The Turk's Cap (T. Sarmaticus, Linn.) comes from the Cape region of South Africa in such quantities that shell dealers all handle it, and collectors can always get specimens. It is a hand some shell, showing beautiful green lights in its pearly mouth. The outside of the shell is normally brown, more or less ruddy toward the apex, and showing streakings of white and orange-red toward the mouth. Underlying the coloured coat is a layer of black, brittle as lacquer, next to the pearl. A tongue of black reaches well into the aperture, encircling the columella. The thin rim of the aperture is edged with this same black, the pearl not reaching the edge. A very little grinding and rubbing removes the outer layers, and leaves the shell pearly throughout. Its alti tude is 2 to 4 inches; diameter 3 to 5 inches. A strange coral-like or mushroom-like growth covers the outside of the operculum.
The shells are made into fancy articles such as purses, stamp cases, scent bottles, pipe bowls and ring trays. The choicest specimens are made into brooches, cuff buttons and earrings.
T. petholatus, Linn., is like the pheasant shells in being smooth and brightly polished, and decorated with bright colours, combined with white, in great variety and intricacy of pattern. They are 2 to 3 inches in altitude and much more dilated at base than the pheasants. The operculum is convex on the exterior, and polished, with a bright green spot in the middle.
Habitat.— Red Sea, Philippines and Indian Ocean.
Sub-genus CALLOPOMA, Gray Shell turban-shaped, dark-coloured, with round aperture, and long, deep columellar groove; outside of operculum spiral with deep central pit, the outer coils with deep-cut grooves or teeth.