282 TURBO. 



5. Turbo. Top-shaped; mouth generally round ; operculum 



shelly. Fig. 368. 



6. Trochus. Top-shaped ; mouth generally angulated ; oper- 



culum horny, consisting of many whorls ; including Elen- 

 chus. Fig. 358,359, 361. 



7. Margarita. Operculum horny, consisting of few whorls; 



pearly. Fig. 362. 



8. Littorina. Similar, not pearly ; including Assi?ninea. Fig. 



363, 363*. 



9. Phorus. Attaching dead shells, stones, &c. Fig. 360. 



10. Monodonta or Odontis. A notch and prominent point 



at the lower part of the aperture. Fig. 366. 



11. Lacuna. With an umbilicus. Fig. 364. 



12 Turritella. Elongated, screw-shaped. Fig. 369 to 371- 

 TURBINATED. {Turbo, atop,) Top-shaped. The term is applied 

 generally to those shells which are large at one extremity, and 

 narrow to a point at the other. Ex. Trochus, fig. 358 ; Turbi- 

 nellus, fig. 382. 

 TURBINELLUS. Auct. {A little top.) Fam. Canalifera, Lam. 

 Siphonostomata, Bl. — Descr. Turbinated, thick, wide near the 

 apex, generally tuberculated ; spire short, depressed, mammil- 

 lated ; aperture rather narrow, terminating anteriorly in an open 

 canal; outer lip thickened within ; columella having from three 

 to five prominent, compressed, transverse folds. The species of 

 this genus are mostly tropical. — Obs. The Turbinelli are a well 

 marked genus of marine shells, the species of which are numerous. 

 No fossil species are known. The genus Canceliaria makes the 

 nearest approach to Turbinellus in some characters, but may be 

 distinguished by the roundness of its form, the raised lines inside 

 the outer lip, and the obliquity of the folds on the columella. 

 Fig. 382 to 384. 

 TURBO. Auct. (A top.) Fam. Cricostomata, Bl. Turbinacea, 

 Lam. — Descr. Turbinated, solid, ventricose, generally grooved or 

 tuberculated ; spire short, pointed ; aperture generally rounded, 

 sub-effuse anteriorly, entire ; operculum shelly, solid, incrassated 

 on the outer side, horny and sub-spiral on the inner side. The 



