GASTEROPODA. 



73 



the Indian seas on coral reefs and rocks. The Ricinula 

 horrida is a remarkable species, being whitish, and covered 

 with black pointed knobs ; the mouth is full of teeth, 

 and is tinged with a violet colour. 



Engina. Gray. — (Enzina Gray.) Shell spiral, varicose, 

 aperture oval, linear, with a broad oblique fold 

 on the lower part of the columella ; the inner 

 lip spread out and wrinkled, the outer lip thick- 

 ened within and toothed ; grooved above. 



Philippi remarks, that this genus approaches 

 some species of Ricinula and Purpura, but is dis- tSlSa. 

 tinguished from them by the outspread wrinkled 

 inner lip. In young specimens the lips are simple, the 

 aperture smooth, the inner lip concave, with distinct folds 

 near the canal. 



Columbella. Lam. — Shell oval; spire short; aperture 

 narrow and notched ; right lip thickened, 

 turned inwards, and swollen in the middle; 

 shell often transversely striated, and much 

 varied in colour ; operculum small and horny. 

 Animal, like the Purpura, only having a 

 narrow foot. — 200 species ; also fossil. 



Small shells, found both in the Atlantic and Pacific, in 

 warm latitudes ; the animals prefer shallow water, about 

 rocks and stones. C. rustica and others are found on the 

 southern coast of Italy. 



Columbellina. UOrb. — Shell oval, thick, ventri- 

 cose ; aperture small, arched, often narrow in the middle, 

 the lower part notched, without a canal, the upper part 

 has a canal carried towards the back, the inside of the 

 outer lip is very much thickened in the middle ; and the 

 border of the columella is also very much thickened out- 

 wardly. — Fossil. 



