124 DR. GWYN JEFFREYS ON THE MOLLUSCA OF THE [Feb. 19, 



variety, as Tvell as a specimen from Corsica, are more or less sraooth, 

 and sometimes destitute of the spiral striae. 



Fossil. Pliocene: Red and Coralline Crag, and Monte Mario. 

 Post-tertiary : Norway and Sweden, Scotch and Irish " glacial " beds, 

 Mammalian Crag, Selsea and Leghorn ; 0-460 ft. 



Among the synonyms are R. minutissima of Michaud and R. 

 multilineata of Stimpsou. Not R. striata of Quoy and Gaimard. 



It is a favourite food of the Eider Duck and other sea- fowl. 



32. RissoA AFFiNis\ Jcifrcys. (Plate IX. fig. 8.) 



Shell oblong, slender, rather thin, semitransparent, and glossy : 

 sculpture slight and indistinct, not sharp and thread-like, spiral 

 striae, of which there are about 1.5 on the last whorl, less than half 

 that number on the penultimate whorl, and mere traces on the next ; 

 the topmost whorl is smooth : colour whitish : spire rather elon- 

 gated : whorls 4, moilerately convex, the last exceeding two thirds of 

 the whole ; apex bulbous and somewhat truncated : suture slight : 

 mouth triangular, sharply pointed above : outer lip thin, somewhat 

 expanded : inner lip reflected on the pillar, and thickened : peristome 

 continuous. L. 0-0125. B. 0-005. 



'Porcupine' Exp. 18/0: Atl. St. Vigo B., 16. A single speci- 

 men from each station. 



Differs from R. striata in being broader |>roportionately to the 

 length, having 4 instead of 5 or 6 whorls, fewer and less distinct 

 spiral striae, and no trace of longitudinal striae, with an expanded 

 mouth and an acute-angled corner at the top. R. arenaria has a 

 shorter spire, stronger and sharper sculpture, swollen whorls, a deep 

 suture, and roundish mouth. The present species is not R. affinis 

 of Beuoit, which is (ex visu typi_) Hydrobia ventrosa. 



33. RissoA ARENARIA, Mighels and Adams. 



Oingula arenaria, Migh. & Ad. in Boston Journ. Nat. Hist. iv. 

 (1842), p. 49, pi. iv. f. 24. 



'Lightning' Exp. St. 2. 



Distribution. Spitzbergen, Y adso (Ferkruzen) ; Bohaslan (Loven), 

 Greenland, Canada, Casco B., and Grand Manan ; 5-40 fius. 



Fossil. Post-tertiary : Greenock and Canada. 



R. mighelsi of Stimpson, who changed the name, because he said 

 this species was not the Turbo arenarins of Montagu. But Montagu 

 never described or mentioned any species of that name. Helix 

 arenaria of INIaton and Rackett (Turbo arenarius of Turton) is 

 Odostomia decussata. R. exarata of Stimpson is a variety of the 

 present species, judging from his description and figure, as well as 

 from a typical specimen given me by the lamented Professor ; this 

 variety was also found by Professor G. O. Sars in Finmark. 



TJie animal was described bv me in the ' Annals and Magazine of 

 Natural History' for March 1877. 



' Allied, sc. to B, striata. 



