Lamarck's Genera of Shells. 69 



6. Conus *. 



Shell turbinated, or inversely conical, convolute. Aperture 

 longitudinal, narrow, not toothed, effuse at the base. 



This genus is the most beautiful, extensive, and interesting of 

 all the spiral, unilocular univalves. It contains the most costly 

 and remarkable shells, whether from the regularity of their form, or 

 the brilliancy and variety of their colours. The most striking cha- 

 racter of the cones is that the whorls of the spire are, as it were, 

 compressed, and rolled one on another, cornet-fashion, so as to 

 leave only the outer whorl wholly visible, and merely the superior 

 margin of all the interior ones. Their general form is that of an 

 inverted cone, being smallest at the base, and increasing in diameter 

 towards the spire, which is usually short, sometimes flattened, 

 sometimes slightly convex, and occasionally somewhat conoidal. 

 The cones inhabit the seas of hot climates, at the depth of ten or 

 twelve fathoms : the animals of this genus breathe only by the 

 branchiae ; their head is furnished with two tentacula, which have 

 eyes near their summit. The mantle is narrow, and above the 

 head is a tube, to convey the water which they breathe to the 

 branchiae. The cones are all sea shells. 



Type, Conus mannoreust. (Idem. Linn.) 



Shell oblong, turbinated, black, with white, subtriangular spots ; 

 spire obtuse, crowned with tubercles ; whorls with concave chan- 

 nellings. Asiatic Seas. PI. v. Fig. 208. 181 Recent species, and 



9 fossil;. 



Fourth Order. 



Cephalopoda. 

 Mantle in form of a sac, containing the lower part of the body. 

 Head projecting beyond the sac, crowned with inarticulated 

 arms, furnished with suckers, and surrounding the mouth. Two 



* A cone. t Of marble. 



I 15c«irlcs the fossil species described at the end of the several genera, and 

 briefly noticed in the preceding pages of these extracts, Lamarck has added a 

 supplement, in this part of the. work, containing the descriptions of many 

 others, which the geologist will find very useful in bin researches in fossil con- 

 chology. 



