Gray o)i Ilelicina. Go- 



Shell spiral, depressed, ovate, imperforated, whorls rapidly 

 enlarging, the last one slightly keeled ; aperture regular, semi- 

 orbicular. Peristome thickened, reflected, base of the columella 

 callous, slightly pitted, becoming smooth. 



History. This genus has been inyolved in considerable obs- 

 curity, as no Linnean author has taken notice of any of its 

 species. 



Patrick Brown in his excellent History of the Island of Jamaica, 

 is, I believe, the first person Avho has mentioned any species of 

 this genus; he describes and figures four, under the name of 

 Cochlea; but he appears to have included and figured Nassa 

 neritina as a species of the same genus, and consequently con- 

 sidered it as a land shell. 



Sloane in his History of the West Indian Islands, has a figure, 

 which may perhaps belong to this genus, but like most of his 

 other figures, it is so badly executed, that there is no certainty to 

 which species or even genus it belongs. 



Lister has" two figures, which appear to be referable to this 

 genus, but they both appear to be the same species, at least, it is 

 very doubtful to what species the figure quoted by Lamarck is to 

 be referred, if it is not the same as the other. Lamarck in his 

 Systema, took notice of the above mentioned figure of Lister and 

 formed a genus of it ; in his Histoire he has added the description 

 of four species, one of which has not fallen under my notice. 



Say, on the article Conchology, published in the American edi- 

 tion of Nicholson's Encyclopo?dia, has described another, which 

 I have not seen. Ferussac has noticed and figured a very remark- 

 able species, under the name of Helix Aureola, which must hare 

 arisen from his only having observed dead discoloured individuals, 

 for some of our specimens have the opercula, which is the first 

 time that a shell with a dentated aperture has been found oper- 

 culated ; the species described in Brown, he appears never to 

 have seen, as he places them in his catalogue of unknown species. 

 We have described sixteen species. 



This genus should be placed near to Cyclostoma^ as both 

 genera have the same kind of animal, except that, as de Ferussac 

 observes, this has the edge of the mantle thickened and formed 



