201 
thus distinctly defining the whorls; the four first volu- 
tions with two distinct elevated ridges winding round 
the middle which gradually disappear in the smaller 
ones; aperture wide oval, ending in a slightly reflected 
open canal; inside pale yellowish white, outer lip very 
thin, inner lip spread. 3...12. Dublin Bay, rare. 
F, Retroversus. Fleming in Wern. Mem. 4. p. 
498. t. 15 f. 2.—F. p. 349.—Whorls five, sinistral, 
transparent, rounded, increasing rapidly (giving the 
shell abellied appearance) smooth and glossy; aperture 
oblong, outer lip joining the body whorl at an acute 
angle; pillar straight, slightly scooped out at the apex 
for the canal, which is shallow regular and short; lines 
of growth scarcely perceptible. 0,08. Zetland. 
* Whorls with longitudinal ribs. 
F, Turricora. #, p. 349.—Muvrex T. Mont. p. 
262. ¢. 9.f. 1—D. p. 744.—Lin. T. 8. p. 144.—Dor. 
Cat. p: 47. t. 14. f. 15.—Puevur T. Blainv. Faun. 
Franc.—Macg. p. 171.—M. Aneuuatus. Don. t. 
156.—Turreted, white and somewhat glossy, the apex 
acute; whorls seven, tapering, rather depressed, and flat 
at the top, ribbed longitudinally, striated transversely, 
I. 3 
