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



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

 more or less imperfect but characteristic. 



y 5. CiTHNA NATiciFORMis ', 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 Up thin, angulated above : inner lip 

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

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

 deep perforation. L. 0-075, 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. 



1/ 1. LlTTORINA OBTUSATA, LiunC. 



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 (JIcAndrew), 

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

 laminavian zones. The recorded localities in the Mediterranean are 

 Toulon (Gffy), S. France (Petit, fide Michaud), Malaga {McAndrew)\, 

 Ajaccio (Requien), Corsica (Susini) !, and Sicily {Philippi, Bivona, 

 Gemellaro, and others). 



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

 and Canada; 0-1360 ft. 



Principal synonyms — Nerita Httoralis, Linne, Turbo retusus, 

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

 2'. pallitttus, Say, T. f abatis, 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. 



j/ 2. LiTTORTNA 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. Probably drifted. 



' Porcupine ' Exp. 1869 : Donegal B., Lough Swilly. 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 Natica. 



