CHAPTER XLVIII: THE SEA SNAILS. BLEEDING 



TOOTH 



Family Neritid^ 



Shell solid, imperforate, top-shaped to patelliform; spire 

 flattened; interior partitions absorbed; body whorl very large; 

 muscle scar horse-shoe-shaped, seen in aperture; columellar 

 region broad; lip simple or toothed; operculum calcareous, 

 spiral or not, with prominent teeth on inner face, one of which 

 locks behind the columellar lip. Snout short; radula long, 

 well developed; tentacles long; eyes on stalks; gill single, on left 

 side, triangular, free; mantle edges without cirrhi. A large family 

 of littoral forms, most of which belong to tropical and sub- 

 tropical oceans. They are greedy vegetable feeders, living on 

 seaweeds. It is said that they are nocturnal in habits, ranging 

 and feeding only at night. They are found near low water 

 on rocks. 



Genus NERITA, Linn. 



Shell thick, smooth or spirally ridged and grooved, porcel- 

 lanous, usually with horny epidermis; outer lip thick, columellar 

 lip flattened, straight, toothed at margin. Animal with festooned 

 mantle border. Feeds on algae by night. A gregarious, littoral 

 genus, in warm oceans, including two hundred living and sixty 

 fossil species. 



The Bleeding Tooth (iV. peleronta, Linn.) is found on 

 the beaches of Southern Florida. It is well known among the 

 coast dwellers. The broad columella bears two teeth, one or 

 both of which are stained with a yellowish, bloody patch. The 

 operculum is shelly and ear-shaped, and shuts more strongly 

 because of a hinge formed by its hook locking behind one of the 

 columellar teeth. The shell thickens greatly just back of the lip. 

 Parallel ridges extend from spire to lip, crossed by fine strize. 



203 



