In the genus Voluta, from volvere, to turn, the shell is oval, more or less tun-bellied. A spiral rising, slightly mammelate, the opening large, the edges notched, without channel; the columellar edge is lightly excavated and arranged in oblique folds. The right edge is arched, thick, or cutting, according to the species.
The animal has a large head, provided with two tentacles. The mouth terminates in a thick trunk furnished with hooked teeth. The foot is very large, furrowed in front, and projecting from all parts of the shell, but without operculum. The Volutæ live on the sands near the shore; sometimes they are found high and dry, left by the retreating tide. Their shells, of various forms, are ornamented with the most lively colours, the surface covered with irregular lines, the tint of which is generally in strong contrast with that of the ground.
Among the more remarkable species illustrated in Pl. XXIII., we may note: Fig. I., Voluta undulata; Fig. II., Voluta cymbium; Fig. III., Voluta delessertii; Fig. IV., Voluta musica; Fig. V., Voluta imperialis; Fig. VI., Voluta scapha; and Fig. VII., Voluta vexillum.
The third family, Conidæ, contains Pleurostoma and Conus.
The genus Conus is especially rich in species, as well as numerous in many individuals. They are much sought after by collectors, many being rare, and so command high prices. The shells belonging to this group present a very remarkable uniformity of shape, at the same time that the colours are very fine, and much varied in design. The shell is thick, solid, inversely conical, wreathing spirally from the base to the apex, the spiral being generally short, the last turn constituting alone the greater part of the surface of the shell. The opening extends nearly along its whole length, occupying all the height of the last whirl. It is always narrow, its edges quite parallel; the columella presents neither fold nor curvature; the right edge is plain, sharp, and thin, detached from the front of the last spiral by a sloping hollow, more or less deep.
Plate XXIII.—Voluta.
I. Voluta undulata. (Lamarck.) II. Voluta cymbium. (Linn.)
III. Voluta Delessertii. (Petit.) IV. Voluta musica. (Linn.) V. Voluta imperialis. (Lamarck.)
VI. Voluta scapha. (Gmel.) VII. Voluta vexillum. (Chem.)