^60 ZOOLOGY. 



their shells are generally strong, rough, and hollow ; and 

 their flesh may with safety be used for food. 



25. Strombus. Screw-Shell. Inhabitant a Limax. 



Shell spiral, expanded ; aperture much dilated, and the lip 

 expanding, produced in a groove, inclining to the left. 

 Plate 5, fig. 25. There are four families in this genus, 

 * Outer Lip dii^i^ated, projecting in linear divisions 

 or claws; ** Lobed ; *'^* Dilated; **** Tapering 

 with a long spire. 



All the Strombt are inhaMtants of the ocean, and are usu- 

 ally found upon rocky shores. 



26. Murex, Rock-Shell. Inhabitant a Limax. 



Shell spiral, roughened with protuberances ; aperture oval, 

 terminating in a narrow strait canal^ inclining back- 

 wards. Plate 5, fig. 26. There are seven divisions in 

 this genus J * SpinouSy with a produced beak: ** 

 having Longitudinal sutures expanded into crisped or 

 curled Foliations, Beak short : *** with thick 

 rounded, protuberant Sutures: **** more or less 

 spinous, Beak wanting : ***** Tvithout spines, having 

 a long, strait, pointed Beak: ****** Tapering, with a 

 long spire^ and short &eoA ; ******* with a toothed 

 columella. 



Most of this genus are found on rocky shores, within the 

 influx of the tide, some few burrow in the sand, and the 

 whole are entirely marine. Their shells are mostly rugged, 



