NERINEA. Defr. _Fam._ Canalifera, Lam.--_Descr._ Turrited, oblong, sub-canaliculated, consisting of numerous whorls; aperture with a strong fold on the columella, one on the outer lip, and one on the inner lip at the edge of the body whorl.--_Obs._ This genus is only found in a fossil state usually in the Oolitic beds, it is not resembled by any other; the strong, prominent folds on the three upper angles of the subquadrate aperture present a singular appearance in a section. One species has been named N. Hieroglyphus. We give N. Goodhallii, fig. 374. NERITA. Auct. _Fam._ Neritacea, Lam. Hemicyclostomata, Bl.--_Descr._ Smooth or ribbed, semiglobose; spire short, sometimes flat, consisting of few volutions; aperture large, semilunar; outer lip thick, entire; inner lip thickened, dentated at the edge, spread over the body whorl, forming a flattened disc; operculum shelly, spiral, with an appendage by which it is locked under the sharp edge of the columella.--_Obs._ These marine shells are known from Neritina by the thickness of the shell and the want of the thick, horny, dark coloured epidermis; from Natica by the flat area produced by the spreading of the thickened columellar lip. N. Peloronta, fig. 330. N. polita, fig. 329. NERITACEA. Lam. A family of the first order of Trachelipoda, Lam. containing the following genera: 1. NAVICELLA. Apex terminal, not spiral; inner lip septiform. Fig. 323. 2. NERITA. Columellar lip septiform, edge with distinct teeth; shell thick. Fig. 330. 3. NERITINA. Shell thin; columellar lip septiform, edge denticulated; generally a thick, dark coloured epidermis. Fig. 324 to 326. 4. NATICA. Having an umbilicus behind the columellar lip, with a spiral callosity. Fig. 327, 328. 5. NERITOPSIS. Edge of the columellar lip with a deep notch. Fig. 331. 6. PILEOLUS. Patelliform; apex central; columellar lip septiform, leaving the aperture small. Fig. 332. 7. JANTHINA. Columellar lip linear; aperture angulated. Fig. 333.