31 

 Family 1. CONVOLUTA. 



Shell ; with the whorls convoluted upon nearly a vertical pilane. 



In this family -'s associated an interesting series in which the whorls of 

 the shell are convoluted one over the other, without obliquely descending, 

 so that 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 

 which exhibit a nearly similar arrangement of the whorls are referred by 

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

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

 next to Pleurotoma, M. De Blainville in the immediate vicinity of Stromhus, 

 and M. Deshayes refers them to his family of Bucciniclce. 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 tins family : — 



Conus. Teeebellum. „ Ovulum. 



Cypilea. Erato. 



Genus 1. CONUS. 



Animal ; disc oblong, rather thin, double-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 emarginated at the base, spire sometimes 

 fat 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 tliroughout 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 chiefly 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, which 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 ; 



