MARSHALL: ADDITIONS TO "BRITISH CONCHOLOGY. " 



133 



Var. distorta Marsh. (/. Conch., vol. 7, p. 251). — Found every- 

 where with the type. 



Var. Candida {Pyramis Candidas Brown, Recent Conch., p. 14, 

 pi. ix., fig. 31). — Usually thinner and more slender; longitudinal ribs 

 obscure or wanting ; without varices or coloured bands. This lives 

 in sea-weeds and corallines at low water, and is the form attributed 

 by Jeffreys, erroneously, to var. arctica Love'n, but that is a synonym 

 of the next. The longitudinal ribs are noticeable only on the upper 

 part of the whorls, and the difference from the type in that respect is 

 only of degree ; but it never has the brown bands round the peri- 

 phery, and is never variced. The name may still be met with 

 in old collections. A very small dwarf of this, dredged off Guernsey, 

 is a little exquisite, and suggests R. contorta Jeffr. 



Var. aculeus A. Gd. --Resembling the last in being without 

 varices, coloured bands, or longitudinal ribs, but having extremely fine 

 spiral striae, which are not always observable in dead specimens. Its 

 shape is that of the type, which is usually broader throughout than 

 the var. Candida. It forms a connecting link with R. proximo, and 

 could easily be mistaken for that species. The Rev. Frank Knight 

 has dredged it at Lismore and Loch Linnhe, Mr. A. Somerville in the 

 Sound of Sleat off Glenelg, and 1 have specimens from the 'Valorous' 

 dredgings in the Arctic seas. It also occurs sparingly in the pleisto- 

 cene beds of north-east Ireland (Praeger) ! 



This is the N. American and Arctic form, which is well figured in 

 Sars' work under the generic title Cinguia aculeus A. Gd. (1841), and 

 is the same form described by Moller as R. saxatilis (1842), and by 

 Loven as R. arctica (1846). A few are apparently smooth, and require 

 a high power to detect the fine spiral lines. It is wonderfully like 

 Jeffreys' R. affinis (i.e., allied to R. striata), a very rare species 

 dredged in the ' Porcupine' Expedition; but the latter has additional 

 equally fine longitudinal striae, which the artist has depicted in his 

 figure, but which the author omits to mention in his description ; 

 indeed he expressly says it has " no trace of longitudinal striae," but 

 in this he was mistaken. Subsequently he must have become 

 acquainted with this northern form, for he wrote in the ' Lightning ' 

 Report — "This variety {arctica Lov.), as well as a specimen from 

 Corsica, are more or less smooth, and sometimes destitute of the 

 spiral striae." 



R. proxima Aid. — 6 to 90 fathoms in muddy sand. Scilly (Smart 

 and others) ; Teignmouth (Burkill) ! Machrie Bay, Arran, 29 f. 

 (Knight)! Killala Bay (Miss Warren)! Antrim (Chaster); from 

 stomach of grey mullet from Norfolk coast (Norwich Museum) ; 

 Lamlash, 12—15 f- '■> Brodick Bay, 40 f. ; Knapdale Locks, 1 1 f. ; 



