TROCHUS. MOLLUSCA. 45 



M. labio, Lam. Shell ovate, conical, ventricose, thick, imperforate, 

 transversely rugous, and spotted with black and red ; wrinkles 

 nodulose ; lip double, sulcated within, and white. 1 inch long. 

 Inhabits coasts of Africa and Asia. Lister, pi. 584, fig. 42. 



Gen. 42. TROCHUS, Lin. 



Shell conical, with the spire elevated, sometimes abbreviated; aper- 

 ture depressed transversely, with the margin disunited in the 

 upper part ; pillar arched, more or less oblique at the base ; 

 an operculum. 



The Trochi are marine shells of a conical form, with the spire more or less ele- 

 vated, and the base generally flat or concave, rarely convex. The greater part of 

 the genus have a rich silvery or nacreous appearance in the inside, and under the 

 epidermis, and many have longitudinal ribs. This genus is very numerous in species. 



T. imperialis, Lam. Shell convex-conical, subventricose, with trans- 

 verse somewhat scaly striae, and the whorls spinous at their mar- 

 gins ; umbilicus large, funnel-shaped ; colour dark olive brown, 

 tinged with violet, and white at the base ; inside pearly. 2J inch- 

 es lono- and 4 broad. Inhabits coasts of New Zealand. Chem- 

 nitz, v. pi. 173, fig- 1714 



T. Solaris ,Lin. Shell convex-conical, with margined spinous whorls, 

 and the aperture semicordate; umbilicus narrow; colour golden, 

 mottled with white. 1 to 2 inches broad and about half as long. 

 Inhabits Indian seas. Chem. v. pi. 173, fig. 1700. 

 This shell is said to have the same faculty as the T. agglutinans of affixing extrane- 

 ous bodies to its shell. 



T. tuber, Lam. Shell somewhat depressed, thick, with the whorls 

 turgid, strongly plaited above, and nodulous at their lower margins; 

 aperture silvery. \\ inch long. Inhabits Mediterranean sea. 

 D'Argenv. pi. 8, fig. 1. 



T. Nilolicus, Lin. Shell conico-pyramidal, base dilated, ponderous, 

 nearly smooth, white, with longitudinal reddish stripes extending 

 over the base ; pillar arched, base truncated ; inner lip nearly en- 

 tire. 3 or 4 inches long and as broad at the base. Inhabits In- 

 dian Ocean. Lister, pi. 61 7, fig. 3. 

 This is a large and beautiful species. When the external coating is taken off the 



shell appears of a brilliant silvery colour. 



T. zizyph'mus, Lin. Shell conical, and the whorls flat, with trans- 

 verse striae, of which those on the margins are largest; base flattish ; 

 colour livid or reddish, streaked longitudinally with darker, broad, 

 undulated irregular stripes. 1 inch long. Inhabits European 

 seas . B.~ Brown's Illust. pi. 45, fig. 16-22. 



T. Pharaonis, Lin. Shell subovate, reddish, with crowded trans- 

 verse rows of rounded beads ; aperture and pillar toothed, and 

 the umbilicus crenated; the beads crimson, black, and white. 10 

 lines long. Red and Mediterranean seas Lister, pi 637, fig- 26. 

 A very pretty shell, remarkable for its granulations, its colouring, and its umbilicus. 



T. cinerarius, Lin. Shell cinereous, orbicular convex, with the apex 

 obtuse ; transversely striated, and waved longitudinal reddish vio- 



