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 semi- 

 circular form, exactly closing the aperture, and 

 furnished internally with a dentiform appendage, 

 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 absorbed 

 by the animal, in proportion as it increases in size, 

 whence it appears to have no columella. 



NERITA Littoralis. 



STRAND NERITE. 



Specific Character. Shell thick, smooth, 

 summit rather obtuse ; whorls four or five, body 

 whorl large, the others small and lateral ; aperture 

 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 

 shores, varying considerably in colour and shape : 



