TROCHUS. 523 



t'. 1 to 4. — Desh. Encycl. Meth. Vers, vol. iii. p. 107-. — 

 Gbvens, Conch. Cab. (ed. 2) pi. 11, f. 84 ; pi. 12, f. 88, 

 96, &c— Philippi, Moll. Sicil.vol. i. p. 179 ; vol. ii. p. 152. 

 — Hanlev, Young Conch, p. 67> 

 Trochus tuberculabus, Da Costa, Brit. Conch, p. 44, pi. 3, f. 1. 



This is a solid opaque and rather lustreless shell, of a 

 somewhat depressed orbicular-conical form, with a scalari- 

 form but not arcuated lateral outline. The exterior is varie- 

 gated with various tints and intensities of reddish, liver, rose 

 colour, or more rarely with dark yellow, on a ground of 

 impure white ; the general style of painting consists of 

 patches of the darker colour radiating from the sutures, 

 succeeded by, or passing into, angularly flexuous, and often 

 interrupted or subreticulated streaks upon the base of the 

 body ; there are generally, also, two or three narrow 

 articulated fillets upon the lower portion of the larger 

 whorls, and sometimes upon the base likewise. Beneath 

 the sutures the surface is adorned witli rather large 

 flexuous irregular blunt knobs, that are longer than they 

 are broad, but are not unfrequently almost obsolete ; 

 below them lie a few scarcely raised rather distant spiral 

 stria?. A somewhat broader belt margins the base of each 

 of the whorls ; above it is a rather deep sulcus, that is 

 minutely honey-combed by close-set obliquely longitudinal 

 lamellae. Numerous spiral lines, that are almost belts 

 upon the younger shells (on which, for the most part, the 

 subsutural knobs are not developed, but the upper spiral 

 lines are often subgranose), encircle the base ; these usu- 

 ally become obsolete in aged individuals. There are six 

 moderately enlarging rather narrow scalariform volutions, 

 which, flattened and subangulated above, flatfish and but 

 little shelving at the sides, and defined by a very strongly- 

 marked suture, terminate in a small and rather pointed 

 apex. The base is plano-convex, anil moderately shelving; 



