98 TRACHELIPODA. 



Genus 56.— NERIT A.— ZamarcA. 



Generic Character. — Shell solid, semiglobose, flattened 

 below, without an umbilicus ; aperture semi-orbicular and 

 entire ; inner lip depressed, septiform, thin-edged, and fre- 

 quently dentated or crenated; outer lip obtuse, and often 

 provided internally with teeth. 



Nerita peloronta. — The Bloody-tooth Nerita. Plate 



XII. fig. 13. Thick, transversely sulcated; gray or red- 

 dish-yellow, with variously coloured bands ; inner lip with 

 two teeth or crenulations, having a bloody mark at their 

 base. One inch long. Inhabits the seas of South America 

 and the West Indies. 



Genus 57— "SERITOIDES.— Brown. 



Generic Character. — Shell strong, thick, subrotund; spire 

 depressed; aperture nearly round; lip almost continuous, 

 having a slight groove only at its junction with the body; 

 no umbilicus. 



Neritoides Utoralis. — The Sbore Neritoides. Plate 



XIII. fig. 24. Smooth, covered with an olive-green, yel- 

 low, brown, or otherwise coloured epidermis, sometimes 

 beautifully banded or chequered beneath it; inside generally 

 purplish-brown ; body very large ; spirt very short and de- 

 pressed. Five-eighths of an inch long. Inhabits the shores 

 of Northern Europe. 



This shell is the Turbo neritoides, and Turbo retusus of Lamarck. 



Gc^nus 58.— NERITINA. —Zawiarcii. 



Generic Character — Shell rather thin, semiglobose, or 

 ovate, flattened below; without an umbilicus; aperture 

 semicircular ; inner lip flattened, and reflected on the colu- 

 mella, sometimes slightly crenated; outer lip destitute of 

 teeth or crenulations on its internal face ; aperture provided 

 with an operculum, having a lateral point. 



Neritina Jiuviatilis. — The Fresh-water Neritina. 



