ODOSTOMIA. 139 



tapering spire, a slight suture, nearly flat whorls, a dif- 

 ferently shaped mouth, and no peripheral keel. 



It is the Voluta plicatula of Dillwyn, and apparently 

 the Eulima unidens of Requien, Turbonella angusta of 

 Leach, and O. vitrea of Brusina. 



16. O. insculp'ta *, Montagu. 



Turbo insculptus, Mont. Test. Br. Suppl. p. 129. 0. insculpta, F. & H. 

 iii. p. 289, pi. xcvi. f. 6. 



Body opaque frosted-white, with a rather large patch of dull 

 claret-red on the back : mantle having the usual fold at the 

 upper angle of the aperture of the shell : snout short, cloven 

 nearly to the eyes, each lobe being deeply curved outwards : 

 tentacles coalescing at their bases, very broad and short ; tips 

 very small, white, and slightly inflated : eyes close together : 

 foot deeply notched in front, forming at each corner a divergent 

 acute auricle, behind which it becomes a little constricted, 

 and terminates in two symmetrical distinct pointed tails or 

 streamers, which describe an angle of separation equal to that 

 of the fore and middle fingers when placed as far apart as pos- 

 sible. (Clark.) 



Shell somewhat cylindrical, with a narrow base, thin, semi- 

 transparent and glossy : sculpture, distinct and regidar spiral 

 incised lines or narrow grooves, which cover the lower three- 

 fourths or even more of the last whorl, and the lower half of 

 each of the preceding whorls ; these lines are not micro- 

 scopical, but visible to a sharp eye without a lens ; the upper 

 part of each whorl below the suture is marked by fine, slight, 

 and numerous flexuous lines in a longitudinal direction, which 

 by crossing the upper rows of spiral striae produce in the latter 

 an imperfectly punctured appearance ; the whole surface is 

 also sculptured with microscopical and close-set spiral striae, 

 which can only be detected in " live " or fresh specimens and 

 at a certain incidence of light : colour pale white, assuming an 

 ivory lustre in " dead " or faded specimens : spire long, some- 

 what turreted, and having a truncated apex ; nucleus obliquely 

 declining, and concealed : ivhorls 6, convex although more or 

 less compressed ; each has a narrow and thick rim immediately 

 below the suture ; the rate of their enlargement is rather quick, 

 the last occupying about one-half of the shell : suture narrow, 



* Engraved. 



