TUERIS. 303- 



lip thickened within ; columella having from three to five promi- 

 nent, 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 kno^mi. The genus Cancellaria 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 columellar. 

 PL xvii. fig. 382 to 384. Seventy-two species are enumerated in 

 Reeve's Monograph. 



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

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

 tuberculated ; spire short, pointed ; aperture generally rounded, 

 sub-efi"use anteriorly, entire ; operculum shelly, solid, incrassated 

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

 Turbines are mostly tropical. — Obs. The only certain means of 

 distinguishing this extensive genus of marine shells from Trochus, 

 is the operculum, which in the latter genus is horny, spiral, 

 and composed of a great number of whorls. The Trochi, how- 

 ever, are in general more conical, and flatter at the under side of 

 whorls, and this constitutes Lamarck's distinction between the 

 genera. Reeve's Monograph contains about thirty species. 

 T. setosus. PI. xvi. fig. 368. 



TXJEGID. (Turffidus.) Puff'ed up, swollen, inflated. This term 

 is applied synonymously with Ventricose. 



TUEEICTJLA. Humph. Melakia, Auct. 



TUEEICULACEA. Bl. The seventh family of the Order Po- 

 lythalamacea, Bl. containing the genus Tm-rilites, fig. 483. 



TTJEEILITES. Lam. {Turris, a tovfer ; Xt0oe, a stone.) Fam. 

 Turriculacea, Lam. Ammonacea, Bl. — Bescr. Chambered, tur- 

 rited, spiral ; septa sinuous and lobate, perforated by a siphon ; 

 aperture rounded, with the outer lip expanded. This genus, 

 which is distinguished from the other Ammonacea by having 

 the spire produced, i. e. not being convolute, consists of several 

 species, occurring only in chalk-marl. PI. xxiii. fig. 483. 



TUEEIS. Humphrey. 1797. Pleukotomus, Montfort. 



