116 UNIVALVES. 



transverse row of long spines ; generally coated 

 with a black epidermis ; length from half to 

 three quarters of an inch, about two thirds as 

 broad. 



This shell has an operculum, which is testa- 

 ceous, covered with a horny epidermis of a 

 semicircular form, exactly closing the aperture, 

 and furnished internally with a dentiform appen- 

 dage, which, when the aperture is closed, lies 

 between a prominence at the lower part of the 

 aperture, and the end of the inner lip. 



The columella, together with the inner part 

 of the spire, and even a part of the lip is absor- 

 bed by the animal, in proportion as it increases 

 in size, whence it appears to have no colu- 

 mella. 



NERITA Littoralis. 



STRAND NERITE. 



Specific Character. Shell thick, smooth, 

 summit rather obtuse ; whorls four or five, body 

 whorl large, the others small and lateral ; aper- 

 ture lunar, rather inclining to oval ; columellar 

 lip not so flat as usual in this genus ; colour 

 various, commonly plain light or orange yellow, 

 red or brown, sometimes prettily mottled, or 

 marked with one or two paler transverse bands ; 

 size about three-fourths of an inch long, breadth 

 rather exceeding the length. 



This species is extremely common on all our 



