88 MOLLUSCA FROM THE CRAG. 



LITIOPA,* Eang. 1829. 

 BUCCINUM (spec.) Quoy ef Gaim. 

 PLANAXIS (spec.) Id. 



QUOYIA. Deshayes. 

 BOMBYXINUS. Lesson. 



Gen. Char. Shell small, thin, corneous, or subhyaline, with a conical or tapering 

 spire, and acute apex ; volutions convex, smooth, or striated ; aperture ovate, and 

 rather large, with a sharp and simple outer lip, continuous to a truncated columella, 

 and a subemarginate base. Operculum, none. 



This genus was established by M. Sander Rang (in the Ann. des Sci. Nat., 

 torn, xvi, p. 303), upon the little Pelagian species found in the Gulf-weed Sargassum 

 bacciferum, and is placed by that naturalist in his systematic arrangement between 

 lanthina and Phasianella. 



The shell, with its truncated columella, much resembles that of Achatina, and 

 might perhaps be considered its marine representative. In the description by the 

 above author, a " sommet pointu" is given as a generic character, which the recent 

 species certainly possesses ; but in the shell from the Crag, which I have presumed to 

 belong to this genus, the apex is very obtuse. In my recent specimens, the first three 

 volutions are contracted and shrunk, being covered with longitudinal wrinkles, as if 

 that part of the shell might be dispensed with, without injury to the animal, like the 

 upper volutions of the Bulimns decollatus, although I have never seen a specimen so 

 decollated. 



1. LITIOPA PAPILLOSA. 8. Wood. Tab. IX, fig. 1, a b. 



LITIOPA PAPILLOSA. S. Wood. Catal. in Ann. and Mag. of Nat. Hist. 1842, p. 539, pi. 5, fig. 11. 

 Morris. Catal. of Brit. Fossils, p. 149, 1843. 



L. Testa ovatd, Icevigatd, tenui, fragili ; apice obtuso ; an/ractibns quatuor, con- 

 vexiusculis; suturis profundis, subcanaliculatis ; operturd ovatd ; labro acuto, simplici ; 

 columella truncatd. 



Shell ovate, smooth, thin, and fragile, with an obtuse, rounded apex, and four 

 slightly convex volutions: suture distinct and deep, or subcanaliculated; outer lip sharp, 

 with a slightly replicate inner lip, forming a minute umbilicus, and a subemarginate 

 aperture, or truncated columella. 



Axis, 5 of an inch. 



Locality. Cor. Crag, Sutton. 



My cabinet contains about half a dozen specimens of this pretty shell, which 

 appears to be distinct from the only recent species I am acquainted with, and which is 



* Etym. AITO'S, simple, and oW/, foramen, or orifice, as given by Hermansen. Or perhaps from Xw, 

 Xtrds, a fine and delicate web, the animal spinning a thread by which it suspends itself to the floating 

 weed. 



