106 



POPULAR CONCHOLOGY. 



ened tentacula, with the eyes at their base, no frontal 

 lobes; the foot simple, no appendages. — 8 or 10 species. 



Natives of New Holland. The type is Trochus melano- 

 stomus. 



Solarium. Lam. (Architectoma Z?o/ta.) — Shell nearly 

 discoid; whorls sharp round the 

 outer edge; not pearly; internal 

 edge of the whorls visible in the 

 umbilicus, which is very wide; aper- 

 ture almost square, margin thin. 

 Animal with a short contractile 

 snout, two cylindrical feelers con- 

 nected at the outer base, where 



Solarium pcrspcctivum. 



there is a distinct thickening for 



the eyes ; the foot has no appendage. Operculum horny 

 and spiral. — 25 species; also fossil. 



The various species of this genus are brought from the 

 coasts of New Holland, Tranquebar, and from the Indian 

 and Chinese seas; they also frequent the shores of the 

 Mediterranean, near Alexandria. The Solarium per spec- 

 tivum, represented in the figure, is frequently called the 

 Staircase-shell. Specimens have been found three inches 

 in diameter ; and as they are elegantly marked with black 

 and straw colour, they are often very beautiful objects. 



Bifrontia. Deshayes. (Schizostoma Browne). — Shell 

 discoidal, plan orbicular, with whorls sometimes not conti- 

 guous; umbilicus deep, keeled at the margin; aperture 

 sub-triangular, somewhat dilated; outer lip acute, sepa- 

 rated by a deep notch at both extremities. (Sow.) — 

 Fossil. 



Greatly resembling the genus Solarium ; but there are 

 no living species. 



