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



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



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

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

 400-1450 fms. 



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

 Deshaves, 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: 23fl,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. Morch), 

 Bay of Biscay (' Travailleur ' Exp.), Villafranca (Hanlet/) ; 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 resembhng 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 tlie last 



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



12, 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 obhquely 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. 



