TROCHID^. 117 



Smssurella (D'Orb.). Shell thin, not pearly, 

 globose ; aperture rounded ; outer margin slit. 

 Animal furnished with an operculum. 

 S. crispata. Fig. 172 ; f. 



lanthina (Lamk.). Ocean-snail. Shell thin, 

 snail-shaped ; aperture four-sided ; pillar twisted ; 

 lip thin, notched at the outer angle ; violet-blue. 

 Animal with a large head and tentacles ; no eyes ; 

 foot small, secreting a float of numerous air- 

 bladders. 



I. communis. Fig. 173 ; n. s. 

 exigua. 

 pallida. 



171 172 173 



Family VII. TEocHiDiE. 



Shell spiral, snail-shaped, or pyramidal ; interior 

 generally pearly. Animal with a short muzzle, 

 eyes, and slender tentacles ; head and sides fur- 

 nished with fringed lobes and filaments ; gill- 

 plume single ; tongue long, naiTow, armed with 

 numerous teeth and hooks. Vegetable feeders. 



Phasianella (Lamk.). Shell polished ; whorls 

 convex ; aperture oval, not pearly ; outer lip thin ; 

 operculum shelly. Animal with long fringed 



