NATICA. 



TESTA subglobosa, vel obovalis, spira brevi* 

 Apertura Integra, scmi-orbicularis, labio coin- 

 mellari obliquo, edentulo, ealloso. Umbilicus 

 plerumque callo spirali instructus, callo umbi- 

 licum interdum penitus obtegente, interdum 

 obsolete. Labium externum acutum, interne 

 Isevigatum. Operculum testaceum vel eorneum* 



Shell sul3globose, oval or oblong*, with a short, some- 

 times very shorty and rarely pointed, spire: aperture semi- 

 circular, large, very seldom effuse ; coluniellar lip oblique, 

 without teeth, generally thickened, sometimes spread 

 thickly over the umbilicus. Umbilicus generally large, 

 furnished within with a spiral callosity which sometimes 

 increases so as to cover the umbilicus, and is sometimes 

 very small, and in a few instances scarcely to be perceived 

 at all. Outer lip sharp edged, smooth within. Operculum 

 horny in some species, shelly in others. 



Such are the char act ei"^ by which the Naticse are to 

 be distinguished: they fprm a rather numerous Genus, 

 dissevered from the Linnean Neritae by Bruguiere; we 

 fear, from the ambiguity necessarily observable in the 

 description, that too many shells are included in it, and 

 that it might have been better, according to the sug- 

 gestion of Lamarck, to have united some of his fossil 

 AmpuUarise with some other shells that have iisually been 

 combined with Nerita and Natica under a new generic 

 appellation. The Genus so formed would consist of those 

 shells which are decidedly marine, like Natica, but which 

 have no callosity in the i^mbilicus, and in that respect 

 reseiT^ble Ampiillaria, How far it is proper to combiuQ 



