44 LITTORINIDiE. 



inner lip having sometimes a pink tinge,, thickened and slightly 

 reflected at the base, behind which is a small chink : operculum 

 ear-shaped, depressed in the centre, with a minute and nearly 

 excentric spire. L. 0-035. B. 0-025. 



Var. paUida. Strawcolour, without the upper, and sometimes 

 Avithout either band, occasionally having merely a pink or 

 reddish-brown streak on the base. 



Habitat : Abundant in the lower part of the littoral 

 zone^ among Zostera marina and small seaweeds^ in the 

 Channel Isles, Dorset, Devon, Cornwall, and the south 

 and west of Ireland. I have also found it sparingly in 

 Langland Bay near SAvansea, and Lough Larne near 

 Belfast. Mr. Lyons noticed it at Tenby, and Mr. Nor- 

 man in the Clyde district. The variety occurred to me 

 feeding on Zostera at Lulworth. R. fulgida is fossil in 

 Calabria (Philippi). It inhabits the Atlantic and 

 Mediterranean coasts of France, as well as Corsica, 

 Piedmont, Sicily, Dalmatia, and Candia. 



This mite of a shell is not half the size of the next 

 species [R. soluta) , from wdiich it differs in colour, want 

 of sculptm'e, shorter spire, having the last Avhorl more 

 expanded, and a less distinct umbilical cleft. It is often 

 encrusted with Melobesia polymorplia. Mr. Clark's first 

 impression, adopted by Forbes and Hanley, that the 

 operculum is not spiral, was properly corrected by him 

 in his OAvn work. He says that the animal does not 

 w^alk straight; that it ^' often jerks or screws the shell 

 a quarter of a round, and carries it almost perpendi- 

 cularly ; '' and that '' on the march the eyes are always 

 under the shell, as are usually the muzzle and foot, the 

 ends of the tentacula only being visible."" I frequently 

 observed it spinning a fine transparent slimy thread, and 

 thus hanging suspended to a bit of seaweed or to the 

 surface of the water. It also swims freely, like its con- 

 geners. 



