380 CYLINDROBULLA. 



entirely open, showing the whole interior of the body whorl as well 

 as the spirally ascending columella, when viewed from below. Type 

 C. beaui. 



Soft parts unknown. Differs from the allied genus Volvatella in 

 the deep sutural slit and less inflated form. 



Of the few species known, one is West Indian, one Mediterranean, 

 the others from Ceylon, New Caledonia and Australia. 



C. BEAUI Fischer. PL 42, figs. 19, 20. 



Shell very thin and fragile, elastic, cylindrical, abruptly and ob- 

 liquely truncated below, rounded above. Pale straw colored ; sur- 

 face smooth ; spire sunken -in an apical umbilicus the raised margin 

 of which is formed partly by the erect inner lip continued back- 

 ward over a half whorl, forming an inner edge to the sutural slit, and 

 partly by the elevated angle of the whorl. Last whorl obliquely 

 truncated below ; viewed from the base the whole interior of the spire 

 and body whorl is visible. Aperture as long as the shell, presenting 

 a nearly round contour almost as large as a section of the cylinder 

 when seen from the base ; very narrow and linear above, and at the 

 top curving backward and extending in a narrow sutural slit two- 

 thirds of a ivhorl in length. 



Alt. 9?, diam. 4f mill. 



Alt. 14, diam. 7 mill. 



Gaudeloupe (Beau) ; Smith's Bay, St. Thomas (Morch). 



Cylindrobulla beaui FISCHER, Journ. de Conchyl., 1856, p. 275, 

 pi. 8, f. 8, 9. MORCH, Mai. BL, xxii, p. 175. 



C. FRAGILIS Jeffreys. PI. 42, figs. 31, 32. 



Shell cylindrical, very shining, hyaline ; constricted and longitu- 

 dinally striate at apex, elsewhere very smooth ; spire loosely invo- 

 lute ; vertex little conspicuous, obliquely attenuated. Aperture 

 narrow above, dilated below and truncate. AU. one-fifteenth, diam. 

 one-thirtieth inch. (Jeffr.}. 



Off West Coast Italy 1521-1536 fms. (" Washington") ; Spezzia, 

 10 fins. (Jeffr.) ; Atlantic Coast of Spain (McAndrew). 



Cylichna fragilis JEFFR., Ann. Mag. Nat. Hist. (2), xvii, p. 188, 

 pi. 2, f. 16, 17. Cylindrobulla fragilis JEFFR., Ann. Mag. (5), x, p. 

 34. 



The " Washington" specimens are adult; the largest is T% inch 

 long. They are microscopically and regularly striated in a trans- 



