TuiiBo. MOLLUSCA. PECTINIBRANCHIA. 299 



Length about |th of an inch ; bands about twelve, apparently interrupted, 



so as to give the surface a checkered appearance ; finely striated spirally 



Probably the fry of the preceding species. 



190. T. mammillatus. — Whorls five, slightly rounded ; spi- 

 rally striated with raised dots. 



Don. Brit. Shells, t. clxxiii — Scilly Rocks. 

 Length and breadth nearly equal; aperture rounded, a few ridges of 

 larger dots give to the whorls a subangulated form. Accorduig to a memo- 

 randum in the handwriting of Da Costa, annexed to one of the specimens 

 figured by Donovan, this shell has been found by Mr Piatt on the Scilly 

 Rocks. 



191. T. crassior. — Shell conical, yellowish-white, with five 

 rounded and deeply divided whorls. 



Turbo laevis, quinque anfractibus apertura subrotunda marginata, Walk. 



Test. Min. 10. t. ii. f. 34 T. crass. Mcmt. Test. Brit. 309. t. xx. f. 1. 



— T. paUidus, Don. Brit. Shells, t. clxxviii. f. 4 — Common in deep 

 water. 

 Length half an inch ; breadth j^oths ; covered with a pale epidermis, 

 which rises in numerous sharp oblique ridges, beneath which are a few obso- 

 lete spiral striae. The whorls are sometimes slightly flattened in the mid- 

 dle ; they are thick and opake. Pillar-lip flattened anteally ; outer-lip thin, 

 joining the body-whorl nearly at right angles. 



192. T. quadrifasciatus. — Pillar with a groove, ending re- 

 trally in a perforation. Shell striated spirally. 



Mmt. Test. Brit. 328. t. xx. f. 7-— T. vinctus, ib. 307. t. xx. f. 3 T. 



canalis, ib. 309— Among sea-weeds, a little beyond low water-mark, 

 common. 

 Length from three to five-tenths of an inch, glossy, of a yellowish horn- 

 colour, with four dark spiral bands on the body, two of which enter the aper- 

 ture, and two are external; between these pairs there is usually a whitish 

 band, where the whorl bends in, rather suddenly, towards the pillar; the outer- 

 lip, at its junction with the whorl, covers a portion of this white space, the 

 external part, however, is usually exposed, and appears as a white band along 

 the line of separation ; the whorls are more or less rounded, and subcarinated 

 on the body- whorl ; but in all, the surface is marked by waved spiral striae, 

 slightly decussated by the lines of growth. The outer-lip, when young, is 

 thin ; but towards maturity it becomes thick, sloping outwardly to a sharp 

 edge ; operculum membranaceous, smooth, yellowish. 



193. T. decussatus. — Whorls five^ rounded ; strongly striated 

 transversely ; finely striated spirally. 



Mont. Test. Brit. 322. t. xii. f. 4. — Among shell-sand, rare. 

 Length about the eighth of an inch, breadth one-half less ; white, glossy ; 

 apex rather blunt ; aperture suboval, a little contracted retrally. 



194. T. margarita. — Whorls four, the first very large, pil- 

 lar-cavity wide ; inside of the aperture with a mother-of-pearl 

 gloss. 



Helix Marg. Laskey., Mmt. Test. Brit. Supp. 143. '\Vern. Mem. i. 408. 

 t. viii. f. 5. — Common on fuci. 



Breadth and height about one-eighth of an inch ; smooth glossy, greenish ; 

 sometimes with one spiral rufous band ; when bleached, it is of a brownish-white 

 colour ; whorls increase rapidly ; rounded, the spire short and blunt ; aperture 



