54 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Jan. 20, 



♦ Porcupine ' Exp. 1869 : 23a. 1870 : Atl. 22. 



Distribution. North Atlantic (' Valorous ' Exp.), Spitzbergen 

 (' Voring;en' Exp.), between the Faroes and Hebrides ('Triton' cruise) ; 

 400-1450 fms. 



C. danielsseni, Friele. 0. procerum of Kiener is, according to 

 Deshayes, a variety of C. fasciatum of Bruguiere. 



3. Cerithium metula, Loven. 



C. metula, Lov. Ind. Moll. Scand. p. 23 : B. C. iv. p. 256 ; v. 

 p. 217, pi. Ixx. f. 3. 



'Lightning' Exp. St. 2, 5. 



•Porcupine' Exp. 1869: 23a, 42, 47,61, 65. 1870: Atl. 1, 2, 

 3, 6, 9, 16, 24-30. 



Distribution. Spitzbergen ('Voringen' Exp.), Finmark to Chris- 

 tianiafiord and North Sea, Shetland, between t!ie Faroes and Hebrides 

 (' Knight Errant ' and ' Triton ' cruises), Fair Isle {Moller, f. March), 

 Bay of Biscay (' Travailleur ' Exp.), Villafranca {Hanley) ; 20- 

 650 fms. 



C nitidum, Mc Andrew and Forbes. 



The number of the spiral ridges varies from 2 to 3 ; and the 

 arrangement of the ridges is not uniform, being more compact or 

 remote in some specimens than in others. 



The type of G. O. Sars's genus Lovenella. 



4. Cerithium gracile\ Jeffreys. (Plate VI. figs. 3, 3 a.) 



Shell, resembling C. metula in shape, but smaller and more slender, 

 semitransparent, very glossy and of a prismatic lustre : sculpture, 

 numerous curved longitudinal riblets, which are crossed by fine and 

 thread-like spiral ridges ; of these last there are three on the last or 

 body-whorl (viz. one below the periphery, the second or strongest 

 encircling the periphery, and the third placed just below the suture) ; 

 the ridges on each of the succeeding whorls are two in number, the 

 larger being central, more prominent, and giving an angulated or 

 keel-like appearance ; the base of the shell is quite smooth and 

 somewhat concave ; the apex is also smooth ; the intercrossing of the 

 longitudinal and spiral striae produces a few slight nodules in the 

 middle of the shell, but not the tuberculated character of the last 

 species : colour glossy white : spire tapering to a blunt point : whorls 

 1 2, rather convex, gradually enlarging ; the last occupies one third 

 of the spire with the mouth of the shell placed upwards ; the first 

 or apical whorl is bulbous and obliquely twisted : suture defined 

 more distinctly than in the other species : mouth irregularly rhombic, 

 with a deep and wide groove at the base as in that species ; its length 

 is about one fourth of the shell : outer lip thickish, indented or 

 scalloped by the spiral ridges : inner lip filmy : pillar flexuous. 

 L. 0-3, B. 0-075. 



' Porcupine ' Exp. 1870 : Atl. St. 3. A single but perfect and 

 living specimen. 



' Slender. 



