LITTORINIDjE. 341 



The presumed subject of these exquisite lines is the 

 Turbo pictus of Da Costa, P. pulchella of Recluz, 

 and Eudora varians of Leach. Lamarck placed it in 

 the old genus Turbo, and not in Phasianella. 



Turbo rugosus of Linne* (71 calcar, Montagu) was 

 said to have been taken by Captain Laskey in lona, one 

 of the Western Islands. It is a rather common Medi- 

 terranean shell, but not British. Turbo castanea of 

 Gmelin (T. mammillatus, Donovan) is West-Indian, and 

 supposed to have been picked up by a Mr. Platt on the 

 Scilly rocks. 



Family IX. LITTORI'NID^, Gray. 



BODY spiral: mantle plain: head snout-shaped; lingual 

 ribbon armed with numerous hook-like teeth, as in the pre- 

 ceding families of the same order : tentacles long, one on each 

 side of the head : eyes placed on very short stalks or tubercles 

 at the outer bases of the tentacles : gills forming a single 

 plume, which is composed of several flat laminar plates : foot 

 having the usual operculigerous lobe, from the hinder part of 

 which in certain genera issue one or two tentacular processes 

 or filaments. 



SHELL conical, never nacreous : mouth obliquely squarish or 

 oval: operculum horny, thin, ear-shaped, and few-whorled, 

 with a lateral nucleus. 



This family, as their name imports, are for the most 

 part littoral : 



" Huge ocean shows, within his yellow strand, 

 A habitation marvellously planned 

 For life to occupy." 



The Littorina, which live on the beach, exposed to 

 frost and cold, snow and rain, do not hibernate, but 

 appear to pass the dreary season of winter without dis- 

 comfort. The equal temperature of the sea and the 

 thickness of their shells protect them from the vicissi- 



