NERITINA. MOLLUSCA. 51 



The animal has a broad short foot, and two pointed tentacula, with the eyes at their 



base. 



N. peloronta, Lin. The Bleeding-Tooth. Shell somewhat ribbed 

 transversely, cinereous or reddish yellow, with longitudinal flexuous 

 black or rose-coloured bands ; spire prominent ; inner lip biden- 

 tated in the middle, and marked with a bloody spot at the base 

 of the teeth ; aperture white, and throat saffron-coloured. 1 inch 

 long. Inhabits South American seas Bonan. 3. fig. 214. 



N. polita, Lin. Shell thick, glabrous, finely striated longitudinally, 

 and variously coloured ; spire flat and somewhat obliterated ; in- 

 ner lip toothed and the outer lip crenulated on the inner margin. 

 16 lines in diameter. Inhabits Indian Ocean. Rumpk. Mus. pi. 

 22, fig. I, K. 

 This shell varies extremely in its colours and markings, whitish, cinereous, and 



clouded, or banded with red, white, dark brown or gray. The aperture towards 



the margin is white, and the throat generally yellow. 



N. versicolor. Lam. Shell thick, transversely sulcated, and tessel- 

 lated with red and dark spots in transverse rows ; inner and outer 

 lip toothed, and the latter striated within, j- inch long. Inha- 

 bits coasts of W. India islands. D'Argenv. pi. 7. 



Gen. 57. NERITINA, Lam. Nerita, Lin. 

 Shell thin, semiglobular or oval, flattened below, not umbilicat- 

 ed ; aperture semicircular ; the left margin flattened ; no teeth 

 or crenulations in the internal face of the outer lip ; oper- 

 culum with a lateral point. 



The Neritinae are river shells, in general smooth on their exterior, and without 

 crenulations or teeth on the outer lip ; and the operculum is furnished with an ap- 

 pendage on the side. The animal has a short foot, and two setaceous tentacula, at 

 the external base of which the eyes are placed. 



N. zebra, Lam. Shell oblong, glabrous, reddish yellow, with longi- 

 tudinal waved oblique black lines ; aperture white ; inner lip den- 

 tated. 1 lines in diameter. Inhabits rivers of South America. 

 Chem. ix. pi. 124, fig. 1080. 



N. corona, Lam. Shell oblong, globose, striated, black, the last whorl 

 crowned with long erect spines ; aperture white , lip denticulated. 



6 to 7 lines in diameter. Rivers of India. D'Argenv. pi. J, fig. 2. 



N. virginea, Lam. Shell globose, oval, smooth, shining, spotted or 

 lined with various colours ; spire very short ; lip denticulated. 



7 lines in diameter. Inhabits rivers in West Indies. Chem. ix. 

 pi. 124, fig. H, L 



N.Jluviatilis, Lam. Shell oval, convex, white, with blackish or 

 brown lines and spots ; spire lateral ; lip toothed. 4 lines in dia- 

 meter. Rivers of Europe. B. Brown's Illust. pi. 43, fig. 4, 5. 



Gen. 58. NAVICELLA, Lam. Nerita, Chem. 

 Shell elliptic or oblong, convex above, with the spire oblique, 

 and concave below ; inner lip flattened, edged, narrow, eden- 

 tate ; a solid flattened operculum with a subulate and lateral 

 tooth. 



