206 NATURAL HISTORY OF OUR SHORES 



Phasianella pulla. This beautiful little mollusc, with 

 a foreign air about it, is local : in some places it abounds, 

 and upon other shores, apparently offering the same con- 

 ditions, it is not to be found at all. It lives on gravelly 

 bottom, and among small stones at extreme low water. 

 It is the only gastropod we have which develops a shelly 

 operculum. 



The operculi of larger specimens form a domestic surgical 

 appliance in old-fashioned homes, where they are known 

 as " Eye Stones," and are used for removing foreign objects, 

 dust or grit, that have got into the eyes. 



The Rissoas are a group of beautiful little molluscs. 

 We have about twenty-five species on our shores. 



Rissoa striata is our commonest species, a little burly, 

 strongly-ridged shell about a fifth of an inch in height. 

 The Rissoas live on the under side of stones, from high- 

 water line to the extreme lowest. 



Littorina littorea (the " Common Winkle "). This is, as is 

 well known, a very abundant species, many hundreds of 

 tons being gathered yearly for market, but it is local, and, 

 strangely enough, is far from common in the Channel 

 Islands. 



Littorina obtusata is a common and pretty shell. As its 

 name implies, it is not so conical as its relatives, but is 

 smooth and rounded. It is subject to much variation in 

 colour, ranging from nearly black to pure white. A bright 

 uniform yellow variety is quite an article of trade with 

 enterprising children in Herm, who collect and sell them 

 at so much a quart, to fancy box makers. 



Littorina rudis is familiar to every visitor to the shore. 

 This little winkle is interesting as living in situations 

 where, for sometimes weeks together, it is only reached by 

 the spray of the sea. Some naturalists hold that it is a 

 mollusc following in the footsteps*of the sand-hopper, etc. 

 gradually forsaking its ocean home and endeavouring 



