The Cross-Barred Shells Family Cancellariidae

THE CROSS-BARRED SHELLS FAMILY CANCELLARIIDAE Genus CANCELLARIA, Lam.

Shell spiral, cross-ribbed upon the whorls; aperture oblong, angulated or drawn out, bearing canal in front; columella with folds; outer lip ribbed; operculum wanting; foot broad in front; head bears tentacles with eyes at base; radula wanting; snout small. Vegetable feeders on tropical and temperate coasts. A single genus of seventy-seven living species.

The West Indian C. reticulata, Linn., is deeply cut by close cross ridges so that the surface is covered with coarse granula tions. Occasionally the radiating ridges are wide apart and wavy. The colour is whitish with markings of brown bands or variegated patches. The columella has two sharp, strong plaits. The shell is heavy and ventricose. Length, 1 to 21 inches.

Cape Hatteras to Florida.

C. Cooperi,

Gabb, has an elongated spire, with the body whorl somewhat constricted above the long, oval aperture. To the very tip the spire is turreted and tuberculated, for the whorls have a distinct shoulder, and the longitudinal ridges form a sharp knob at every crossing. The whorls are elegantly marked with narrow, dark brown lines. The interior shows a series of ridges, and three basal, oblique plaits cross the columella. Length, 2 inches.

This handsome shell comes from deep water off the Cali fornia coast. Fishermen drawing their nets haveln many places learned that it is to their financial advantage to save all the strange shells they take with their fish. The conchologists have thus obtained some of their best treasures. Many unknowns have been brought to light by this means within recent years. When we consider how new our west coast is compared with the Atlantic seaboard, it is not surprising that more new forms are reported from that quarter. Most of the new specimens are sent by their

103 The Cross-barred Shells owners to Dr. Da11 at the United States National Museum in Washington, D. C. He has given names to them. The speci mens thus for the first time christened by a scientist are the "types" of the new species. Specimens found later are com pared with the type to determine what they are. "Types" are usually preserved in great museums.

C.

cancellata, Linn., has a thick shell studded all over with sharp points left by the intersection of deep furrows crossing each other. Two bands of brown decorate the body whorl, one cir cles each whorl above. The ground colour is creamy white. The throat of the shell also has sharp ridges and teeth.

This ornamental shell is hidden in life by sand. The foot, unprotected by an operculum, has a sandy coat on the bottom, so that when it is pulled in the aperture seems to be plugged with sand. The species is found on sandy bottoms at four or five fathoms depth. The sand is no doubt a protection. The creature is slow and timid. lt can extend the head and foot to surprising lengths. Length, t -to inches.

Habitat.— West Africa, Mediterranean Sea.

C.

Stimpsonii. Calkins, is a colourless tropical species. Its whorls are angulated and noduled, the surface below the shoulder decorated with rows of smaller projections. There are two plaits on the columella. The oval aperture ends in a short canal. Length, inch.

Habitat.— Cape Sable, Florida.

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