1 12 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Mar. 6, 



•Porcupine' Exp. 1870: Atl. St. 16, 17, 17«. Five specimens, 

 more or less imperfect but characteristic. 



y" 5. CiTHNA NATiciFOBMis *, Jeffreys. (Plate XX. fig. 11.) 



Shell obtusely triangular with an eccentric spire, thin, semitrans- 

 parent, and glossy : sculpture, a few rather strong spiral striae on the 

 base or underside, besides the usual umbilical ridge : colour white ; 

 spire very short : whorls 3, convex, the last occupying three fourths 

 of the shell ; apex bulbous : suture very deep : mouth nearly circular, 

 large and expanding : outer lip thin, angulated above : inner lip 

 filmy : umbilicus large, enclosed by a sharp carved ridge or stria 

 (sometimes by an outer and an inner stria), and ending in a small but 

 deep perforation. L. 0075, B. 01125. 



'Porcupine' Exp. 1870: Atl. St. 17a. Three more or less 

 imperfect specimens. This differs from the last species in shape, 

 sculpture, shorter spire, and fewer whorls. 



IX 1. Ltttorina obtusata, Linne. 



Turbo obtusata, L. S. N. p. 1232. 



L. obtusatus, B. C. iii. p. 356 ; v. p. 205, pi. Ixv. f. 1. 



' Porcupine' Exp. 1869 : St. 9. Dead, and probably drifted by a 

 current or voided by a fish. 



Distribution. Tenissei G., Novaia Zemblia, White Sea, Iceland, 

 Faroes, Finmark to Gibraltar, Mediterranean?, Azores {McAndrew), 

 Davis Strait to New York ; 0-15 fms. Living in the littoral and 

 laminarian zones. The recorded localities in the Mediterranean are 

 Toulon ( (ray), S. France {Petit, fide Michaud), Malaga (McAndrewy., 

 Ajaccio (Requieti), Corsica {Susini) !, and Sicily (Philippi, Sivona, 

 Gemellaro, and others). 



Fossil. Post-tertiary : Scandinavia, British Isles, S.W. France, 

 and Canada; 0-1360 ft. 



Principal synonyms — Nerita littoralis, Linne, Turbo retusus, 

 Lamarck, and Littorina arctica, Mciller ; and as some of the varieties 

 2\ pallia f us, Say, T. fabnlis, Turton, and L. limata, Loven. 



Mr. Duprey found in Jersey a monstrous specimen which had 3 

 tentacles and 3 eyes. The middle tentacle was bifid ; and the eye 

 belonging to it was double and presented two small points in juxta- 

 position. The other eyes were simple or regular. 



(^ 2. Littorina rudis, Maton. 



Turbo rudis, Mat. Nat. Hist, and Antiq. West. Counties, 1797, 

 p. 277. 



L. rudis, B. C. iii. p. 364 ; v. p. 206, pi. Ixv. f. 3, 3 a, 3 b. 



' Lightning' Exp. St. 5. Probablv drifted. 



' Porcupine ' Exp. 1869 : Donegal B., Lough S willy. 1870 : Atl. 

 Vigo B. 



Distribution. Coasts of N. Atlantic on both sides, from Spitzbergen 

 to Lisbon and Davis Strait to Staten I. in the U.S., Iceland, Van- 



' Shaped like a Kai/ca. 



