31 

 Eamny 1. CONVOLUTA. 



Shell; witli the whorls convoluted upon nearly a vertical plane. 



In tins family is associated an interesting series in wiiicli the whorls of 

 the sheU are convoluted one over the other, without obHquely descending, 

 so tliat the sutural extremity remains almost upon a plane with the top of 

 the spire. It is grouped upon rather an artificial basis, because the Olives 

 M'liich exliibit a nearly similar arrangement of the whorls are referred by 

 their affinities to the family Pnrjnirifera. The Cones have likewise been 

 removed to various situations in the natural order, Mr. Gray places them 

 next to Pleurotoma, M. De BlainviUe in the immediate vicinity of Strombus, 

 and M. Deshayes refers them to his family of Bicccinidce. The Cowrey 

 with its enveloping mantle, is certainly very different in appearance from 

 the Cone, in which the mantle is of very limited proportions ; but the Ovu- 

 lum and the Cowrey are very closely allied. The following are the genera 

 referred to this family : — 



CoNus. Terebellum. Ovulum. 



Cypr^a. Erato. 



Genus 1. CONUS. 



Animal ; disc ohlong, rather thin, douhle-edged, oval behind, 

 abruptly truncated in front ; head obtusely cylindrical, with a 

 rather short trunk ; tentacles short and stout, with the eyes 

 placed upon them at a distance of about one fourth of their 

 length from the summit. Operculum very small, horny, some- 

 times wanting. 



Shell ; conical, slightly einarginated at the base, spire sometimes 

 flat and obtuse, sometimes sharply acuminated ; aperture longi- 

 tudinal, mostly narrow ; lip simple. 



The Cones constitute one of the most natural and best defined generic 

 groups tlu-oughout the class ; they present a great similarity of structure, 

 and the species are remarkable for the elaborate design and brilliancy of 

 their colours. The differences of form consist cliiefly in the depression or 

 elevation of the spire, the attenuation or inflation of the whorls, and in 

 their spiral edges being plain or coronated; there are, however, many 

 striking variations, wliich though apparently of marked specific importance 

 are yet common to different individuals of the same species. Some, for 

 example, are found with the spire at one time plain, at another coronated ; 



