18 



CHAPTEa IL 



WHELK — COWRY — COCKLE — PHOLAS — LIMPET — SEA-WEEDS 

 ON SHELL — BALANUS — PURPURA — ^MUSSEL — ^PERIWINKLE, 

 YELLOW — PERIWINKLE, COMMON — TROCHUS. 



Descending to the shore, we shall probably 

 see at our feet many shells, or fragments of 

 shells, which have been washed upon the beach 

 by the advancing tide, and which having lodged 

 behind a stone, or being sunk into the wet sand, 

 remain behind when the waves retreat. These 

 shells are almost invariably empty, their in- 

 habitants having either died a natural death, or 

 having fallen victims to some ravenous inhabi- 

 tant of the sea. 



The strong house with which most of these 

 creatures are furnished would seem to be an 

 effectual defence against the efforts of open foes, 

 while the sensitive nervous nature with which 

 they are gifted would appear to secure them 

 from insidious attacks. Yet the hard, stony 

 shells, that turn the edge of a steel knife, are 

 constantly found to be perforated by creatures 



