20 LITTORINID^. 



stone districts ; England and Wales (^Listei-), /3 Scot- 

 land, Edinburgh. 



Animal grey-brown. 



Shell halt" an inch long, and four-tenths of an inch 

 wide, solid, grey or purplish-yellow, mostly purple 

 at the tip, often marked with two rows of purplish 

 brown spots ; spire composed of five rounded volu- 

 tions, marked with numerous close-set raised spiral 

 strife and finer longitudinal ones between them; 

 aperture round with a smalt angle at top, and an um- 

 bilicus behind the pillar ; operculum hard, horny ex- 

 ternally, and marked with a single depressed spiral 

 line, from which some very fine striae radiate towards 

 the circumference. 



Lister (^Tah. Anat. iv. f. 1. 2. 3.) gives some ac- 

 count of the anatomy ; and a very detailed description 

 has lately been published by the Rev. Mr. Berkeley 

 {^Zool. Journ. iv. 278.). 



The tips of the tentacles have a bright brown 

 spot very visible to the naked eye, Avhich Montague 

 considered as a second eye. It is the organ of 

 smell. The tentacles, in repose, are annulated, 

 resting on the sides of the trunk. 



Brard describes two unequally compressed carti- 

 laginous pieces, one on each side of the buccal cavity. 

 They are rounded on one side, thin and sinuous on 

 the other ; slightly tubercular and whitish. 



Fam. 2. LITTORINIDiE. 



Trunk produced and wrinkled, not retractile ; ten- 

 tacles far apartj on the side of the head ; eyes 



