THE HELMET SHELLS - CAMEO SHELLS - FAMILY CASSIDIDAE Shell heavy, thick, sub-globular, or three-cornered; spire short; whorls sometimes varicose; aperture long, ending in front in a recurved channel; columella thick, widely spread out, with folds; outer lip thickened at margin and toothed within; oper culum horny, concentric, fan-shaped; head large; tentacles with eyes at base; snout extensible; foot large; mantle large.
An energetic, predatory family, living along sandy shores of warm oceans, and preying upon various bivalve mollusks.
Genus CASSIS, Lam.
Characters of the family. Twenty-five species.
The Red Helmet or Bull's Mouth (C. rufa, Linn.) has a cowry-shaped brown shell, oval in outline, but with a broad spire. The surface is finely cancellate4. The body whorl has three rows of low knobs. The broad, toothed lips are clouded and barred with bright orange-red, shading darker between the teeth. A wide enamel callus: coats the columella. Length, 5 to 7 inches.
Habitat.— Indian Ocean, Japan.
The Black or Cameo Helmet Shell (C. cameo, Stimps.) was wrongly named C. Madagascarensis, by Lamarck, for it is not an inhabil'Iant of Oriental seas. It is yellowish with brown markings. Tile distinguishing character is the painting with dark brown of the spates between the ridges that surround the aperture. These cross streaks are short and distant on the lip; longer and close-set on the columella. Three spiral ridges revolve about the body whorl, bearing knobs. Length, io inches.
Habitat.—Beaufort, N. C., to West Indies.
The Sardonyx Helmet (C. tuberosa, Linn.) has a three cornered outline, and the surface is crossed by fine lines, both The Helmet Shells. Cameo Shells longitudinal and spiral. Three rows of distant nodules occur
on the hump-backed body whorl. Brown blotches of varying size ornament a yellow ground. The pale ground of the broad columella is overlaid by dark brown streaks between the plications, and toward the posterior end of the aperture a big patch of bright chestnut occurs. A few large brown spots are disposed around the margin of the outer lip. This is one of the pre ferred cameo shells; the white figure stands out clearly against a black background. Length, 6 to 8 inches.
Habitat.— North Carolina to West Indies.
The Flame Helmet (C. flamtnea, Linn.) has a high, singly ridged, conical spire, and is decorated with browns in flame-like crescentic patterns, even on the face of the expanded columellar lip. Big blackish spots follow the lip margins around. Strong knobs range along the shoulder of the body whorl, with two fainter and shorter parallel rows lower down. Length, 4 to 6 inches.
Habitat.— West Indies.
The Horned Helmet (C. cornuta, Linn.) is studded with three spiral rows of tubercles, between which the surface is finely honeycombed and has series • of parallel rows of fine dots, the area clouded with brown. Blotches of dark brown occur on both lips and on the rows of knobs. The colour is creamy white. One strong varix runs down behind the columellar lip.
This is not only the giant of its family, reaching a foot in length, but its distribution is over „a belt that encircles the globe. It inhabits the Indian Ocean, the Philippines, Japan and the West Indies. In cameos it gives a white raised_figure on an orange or pink ground.