64 LITTORINID.E. 



yet when closely examined exhibits for the most part 

 (especially upon the body-whorl) a dense array of minute 

 and rather indistinctly indented spiral lines. Beneath the 

 delicate pale bulf or fulvous horn-coloured epidermidal 

 skin, the surface is either of an uniform whitish tint, or else 

 is banded with four narrow zones of chestnut or chocolate 

 brown. Of these, the first of M'liich seems always to 

 commence at some small distance from the sutural line, 

 there are four upon the body-whorl, two of whicli are 

 generally continued upon the succeeding turn. In the 

 variety bifasciata, v/hich is generally smaller, and some- 

 times broader than in the type, the bands unite in two 

 broad pairs, that are frequently of a dark flesh-colour. 

 There are five quickly increasing whorls, of which the 

 apex is small and blunt, and the body (viewed underneath) 

 occupies from three-fourths to three-fifths of the entire 

 length of the shell. Their attenuation above is alwaj's 

 rapid, but their height and degree of convexity is subject 

 to much variation ; the whorls, however, are always more 

 rounded below than above, and as a general rule it may 

 be observed, that the shorter is the shell, the more rounded, 

 horizontal, and abbreviated are its turns, and the more 

 ample is the mouth ; the more elongated the figure, the 

 more produced flattened, and oblique are its volutions, 

 and the smaller is the aperture. No angularity is ever 

 observable (as in crassior) beneath the simple suture. 

 The basal declination of the body is generally sudden, and 

 its commencement occasionally subangular, though more 

 usually rounded. The mouth is longer than broad, is 

 ovate or rounded ovate, and in general is equal or sujierior 

 to half the length of the shell ; but in the slender variety 

 (gracilior) only occupies about two-fifths of it. The 

 outer lip is acute, simple, disposed to project and expand. 



