The Purples. Dog Winkles 



The Fingered Castor Bean Shell (R, digitaia. Lam.) has 

 long finger-Hke processes on the lip. Its spiny exterior is colour- 

 less; the aperture, orange-red. Length, i^ inches. 



Habitat. — Central Pacific Islands. 



The largest species is R. hystrtx, Linn., a ponderous shell, 

 with flattened spire and broad shoulder, tawny brown, set with 

 stout, short fingers. The aperture is small and round; the flaring 

 lip and columella are rose-coloured. Length, i^ to 2h inches. 



Habitat. — Central Pacific Islands. 



The Mulberry Shell (R. morus, Lam.) is well named. Its 

 white spire is covered with rounded black (rarely white) nodules. 

 The aperture is violet. Length, § to i inch. 



Habitat. — Polynesia. 



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, i^ 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, i inch. 



Habitat. — West coast United States. 



The Sad Unicorn (M. liigubre, 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, i inch. 



The Giant Unicorn (A/, giganteum, Less.), yellow, fusiform, 



47 



