THE UNICORN SHELLS Genus MONOCEROS, Lam.
Distinguished from Purpura by the distinct tooth or horn developed on the outer lip near the canal. A small genus almost exclusively confined to the west coast of America.
The Angled Unicorn (M. engonatum, Conr.) lives among seaweeds on rocks swept by the tides. Its whorls are square shouldered, set apart by a deep winding suture, and forming a prolonged spire. The whorls bear fine spiral striations, crossed by wavy lines of growth. The lip is toothed, the horn is sharp and long. The shells are like the rocks in colour; especially when wet. Length, 1 inches.
Habitat.— West coast of United States.
The Pebbly Unicorn (M. lapilloides, Conr.) is a solid little shell, plump in form, and marked so that it resembles a granite pebble. The small aperture has a row of knobs above the horn.
Length, 1 inch.
Habitat.— West coast United States.
The Sad Unicorn (M. lugubre, Sby.) reaches Southern Cali fornia beaches from its native Mexican coast. It is dull and heavy, the aperture even, a dark brown. The lip bears white knobs of small size. Length, 1 inch.
The Giant Unicorn (M. giganteum, Less.), yellow, fusiform, 47 The Purples. Dog, Winkles with revolving lines of 'brown on the smooth whorls, and the tell-tale basal tooth on the lip, is the largest of the genus. Length 3 to 5 inches..
Habitat.— Chili.