LTTTORINA RUDIS. 657 



that place, but correspond both in size and form with a recent one from the 

 Isle of Man sent me by M. Dautzenberg under the present name, as well as with 

 some given in Brown's 'Illustrated Conchology' as a variety of L. rudis. Jeffreys' 

 description is that it is " large, globular, thick and nearly smooth." He states it 

 has been found at Oban and in Dublin Bay, and that specimens of it are sometimes 

 nearly an inch in length. 



Var. nigrolineata (Gray). Plate LIII, fig. 9. 



1839. Littorina nigrolineata, Gray, Zool. of Beechey's Voy., p. 140. 

 1846. Litorina nigrolineata, Philippi, Abbild., vol. ii, p. 104, pi. i, figs. 17 — 19. 

 1853. Littorina rudis, var. nigrolineata, Forbes and Hanley, Brit. Moll., vol. iii, p. 34. 

 1859. Littorina rudis, var. nigrolineata, G. B. Sowerby, 111. Ind. Brit. Shells, pi. xii, fig. 13. 

 1912. Littorina saxatilis, var. nigrolineata, Dautzenberg et Fischer, Camp. Scient., Prince de Monaco, 

 vol. xxxvii (Mollusques), p. 196, pi. ix, figs. 28, 32. 



Varietal Characters. — Shell ovate, suborbicular, pale and whitish with dark, 

 impressed spiral lines ; spire short ; whorls convex ; suture distinct ; mouth ovate ; 

 inner lip dilated in front (Gray) ; outer lip sharply incurved. 



Dimensions. — L. 14—18 mm. B. 10 — 14 mm. 



Distribution. — Recent : British seas. 



Fossil; Icenian Crag (not uncommon). 



Pleistocene : Selsey, probably elsewhere. 



Remarks. — A fair number of the Crag Littorinas are ornamented conspicuously 

 with reddish or dark-coloured spiral bands. Some of these are distinctly of the 

 rudis type, with convex whorls, an incurved lip and a deep suture, as are those 

 here figured under the present name, the coloured bands varying in number. 

 Others, for which I adopt Wood's name of vulgaris (see p. 647), group themselves 

 with L. littorea, having flattened whorls, a shallow suture and a straight lip, agreeing 

 with that species in form, but being smaller in size than the type. 



Var. rudissima (Bean). Plate LIII, figs. 10, 11. 



1844. Littorina rudissima, Bean in Suppl. to Thorpe's Brit. Mar. Conch., p. 266. 

 1912. Littorina saxatilis, var. rudissima, Dautzenberg et Fischer, Camp. Scient., Prince de Monaco, 

 vol. xxxvii (Mollusques), p. 198, pi. x, figs. 4 — 20. 



Varietal Characters. — Shell of medium size, strong and solid, turreted, with a 

 pointed and projecting spire ; whorls 5 or 6, convex, well defined by the suture, 

 the last ventricose ; ornamented by numerous spiral and prominent lines. 



Dimensions. — L. 10 — 18 mm. B. 8 — 15 mm. 



Distribution. — Recent: coasts of Great Britain and of Western Europe. 

 Fossil : Icenian Crag : Bramerton. 



