MANGELIA. 477 



distinct species. Of these we shall first describe the 

 common rugged form, which is taken from a rough bottom, 

 and then indicate those points alone by which the smoother 

 and more elegantly coloured varieties differ from it. 



The shell is moderately strong, a little glossy, and either 

 of an uniform dark brown (rufous when dead) or with the 

 elevated portions of its surface paler, and the depressed 

 parts of a darker tint. The shape is turreted-fusiform, the 

 form being attenuated at both extremities, but more quickly 

 and bluntly so anteriorly, more slowly and acuminately so 

 posteriorly, where the spire tapers to a very fine point. 

 Numerous fine raised spiral lines (that are not microscopic 

 and densely disposed as in costata) traverse the entire sur- 

 face of the shell, and these are again partially decussated 

 by some fine and crowded longitudinal wrinkles, that are 

 peculiarly oblique, and are most apparent beneath the 

 sutures. Ten or eleven longitudinal somewhat flexuous 

 pliciform ribs, whose intervening depressions are about 

 equal in extent, adorn each of the two or three principal 

 volutions ; they are not abruptly prominent, but rather 

 broad based and laterally shelving, are least developed 

 above, project and widen below ; and often become some- 

 what obsolete towards the basal extremity of the shell 

 where the spiral sculpture is most marked. The spire, 

 which is half as long again as the body, is composed 

 of nine or nine-and-a-half coils, the larger ones of wliich 

 are a little refuse below the extremely fine suture, and 

 swell out moderately below ; they are not peculiar either 

 for height or volutional increase. The body is not ventri- 

 cose, but merely moderately convex ; it forms a rudi- 

 mentary tail at the bottom of its quick but not planulate 

 basal declination. The colouring of the narrow aperture, 

 which occupies from one -third to two-fifths of the ventral 



