194 POPULAR CONCHOLOGT. 



the West Indies, is doubtful as regards its 

 habits, some authors supposing it to be ma- 

 rine.* Many of the species are covered with 

 an epidermis. The N. flumatilis is found in 

 the rivers of England adhering to stones. This 

 shell is often covered with incrustations. 



61. Nerita. — Shell thick, having no um- 

 bilicus ; spire nearly hid ; 

 mouth semicircular ; in- 

 ner lip flattened, and 

 frequently toothed, as 

 well as the outer ; oper- 

 culum shelly. Animal, 

 head furnished with two 

 pointed tentacula having eyes at the base ; foot 

 large. Marine. — There are 27 species recent, 

 and 10 fossil. 



The shells of the Nerita are often beautifully 

 marked and sculptured ; they inhabit the East- 

 ern and American seas, a few species only being 

 European. The Nerita peloronta is called the 

 Bleeding Tooth, from the red appearance of the 

 teeth on the inner lip. Many of the species 



* Gray says it is only found in the sea. 



