THE MITRE SHELLS FAMILY MITRIDAE. Shell fusiform, solid, sometimes ovate-oblong; spire pointed, never papillary; columella plaited, the smallest plaits nearest the base; aperture narrow, often half as long as the shell; lip thin, usually toothed; epidermis thin or wanting. Animal with small, narrow head, bearing tentacles with eyes and a cylindrical extensile proboscis; mantle enclosed; foot small; radula variable, the laterals in many broad and comb-like; siphon long, with anterior appendage.
Genus MITRA, Lam.
A large genus between Voluta and Marginella. Species, 200, in Tropics; the finest inhabit Australia and the Philippine Archi pelago. They are gregarious, nocturnal mollusks, avoiding the light, hiding by day under rocks and coral masses along the reefs Some burrow in sand. The heavy shelled species are sluggish. All are most active at flood-tide. Ribbed species crawl about coated with sandy mud, which is a protection from enemies. Some species emit a purple fluid when disturbed. The shells are among those most desired by collectors.
American tropical species are among the large and gaily painted forms. Those which dare the colder shores are smaller and less ornate. Dr. Daly describes seventeen species on our southwest coast.
The Episcopal Mitre (M. episcopalis, d'Arg.) is fortunately a shell widely distributed in tropical seas, else it would not be within the reach and means of amateur collectors. As it is, no one needs to go without it. lts tapering spire of smooth, solid whorls is creamy white, overlaid with orange spots in regular winding rows. The spots just below the sutures are large and irregular. Those farther below are orderly close squares. The large spots are darker than the others. The lip is toothed toward its base. Length, 4 to 5 inches. Ceylon, Philippines.
87 The Mitre Shells The Papal Mitre (M. •papalis, Linn.) is thick and stout, painted with close spots of purplish crimson on a white ground, the spots uniformly small and squarish, often touching each other. The lip is crenate. Length, 3 to 4 inches.
Habitat.-- Island of Annaa, Pacific Ocean.
The Pontifical Mitre (M. pontificalis, Lam.) is smaller than the two already described, and has its whorls strongly coronated with a spiral row of triangular cusps that stand erect. Below these are some impressed lines deeply punctured with rows of pinholes. The white ground is painted with irregular rows of orange-red spots. The animal is cream-coloured, with opaque white dots. Length, 2 to 3 inches.
Habitat.— Annaa and Tahiti Islands.
Habitat.— Deep water off the coast of Central America. Swainson's Mitre (M. Swainsoni, Brod.) is represented by a variety,Antillensis, Dall,found in deep water off Cape Lookout and among the West Indies, and in the shallower regions on the west coast. It is a slender, graceful form, with slightly rounded whorls scored with shallow, spiral lines, cancellated by cross lines of growth. The outer lip widens a trifle at base. The columella bears the four strong, oblique folds near the middle. Length,3 to 4 inches. The Moor Mitre (M. maura, Swains.) a dark brown, fusiform shell, faintly lined both ways, with conspicuous ridges on the columella, is, while alive, covered with a black epidermis. Length, to 2 inches.
Habitat.—California coast.
Genus MITRAMORPHA, Ads.
Minute shells of this genus have stouter shape, but most of their characters proclaim their relationship with the true mitres. The columellar folds are often lacking.
The Rough Mitramorpha (M. aspersa, Cpr.) is brown and strongly cancellated. Length, I inch.
Habitat.—California.
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