34 LITTORINID^. 



fringed with fine and short cilia, and furnished at the left hand 

 or upper corner with a long but slight filamental process : snout 

 comparatively large, bilobed: tentacles cylindrical, long and 

 slender, strawcolour with a yellowish-brown streak down the 

 middle of each, thinly clothed with fine and short hairs re- 

 sembling those on the border of the mantle : eyes on small off- 

 sets : foot divided into two parts ; the front part is transversely 

 oblong, and the hinder part is triangular, or shaped like a 

 spear-head, and ends in a blunt point ; the line of division is 

 margined by a purple border : appendage long. Shell thinner, 

 ribless, and horncolour, with a much shorter spire. 11. port/em, 

 Loven, Ind. Moll. Scand. p. 24. 



HABITAT : Laminarian zone, in Guernsey, Hants, 

 Sussex, Dorset, and Devon; Barmouth (J. G. J.) ; Bantry 

 (Barlee) ; Connemara (Farran and others) ; Belfast 

 (Thompson and Hyndman) ; Lough Strangford, 720 f. 

 (Dickie) ; west coast of Scotland, and Shetland (Barlee 

 and J. G, J.). The 1st variety inhabits the last two 

 districts, and the 2nd the West Voe at the Whalsey 

 Skerries in east Shetland. " Subfossile," Nice (Risso) ; 

 post-glacial bed in Norway, 50 feet (Sars). Living 

 from Finmark to the Cattegat, in 1-40 f., as R. rufila- 

 brum and R. porifera ; north of France to Vigo, the 

 Mediterranean, Adriatic, and ^Egean, in 725 f., as R. 

 violacea-, Villafranca (Hanley), as R. rufilabrum. 



The animal of the variety porifera twirls about rest- 

 lessly at intervals, using its foot as a pivot ; the male is 

 not half as large as the female. The shell of the ordinary 

 form varies extremely in size, as well as in the length 

 and sharpness of the spire. Mediterranean specimens 

 are more narrow and slender, and their colour is much 

 brighter, presenting the same analogy that exists between 

 southern and northern specimens of R. costulata. That 

 species differs from the present in having a longer 

 and more tapering spire, a smaller base and contracted 



