PERIWINKLES WHELKS. 23 



alimentary canal, and is generally plaited in a longi- 

 tudinal direction." * 



Any one who has clambered over rocks by the sea- 

 side must have been struck with the peculiar appear- 

 ance they frequently present of having been bored 

 into a number of holes, to a depth frequently exceeding 

 half an inch. Now, it is a curious circumstance that 

 these excavations in the solid stone are formed by 

 the Limpet. The animal lies in these sleeps all day 

 long, and awakens at night to go abroad in search of 

 food. 



This singular fact was first made known by Mr 

 Lukis, of Guernsey ; a gentleman whose studies have 

 done much towards enlightening us upon several 

 hitherto obscure portions of Natural History. He 



" The locomotion of the Limpet may be ascertained 

 by marking one individual to avoid mistake, and 

 then observe its cautious roaming, and regular return 

 to its favourite place of rest, where the shell will be 

 found exactly to correspond with the surface of the 

 rock to which it is attached. Here it will rest and 

 sleep, and only relax its strong adhesion to the rock, 

 when the muscular fibre becomes exhausted by long 

 contraction, in which state a sudden blow, horizon- 

 tally, will easily displace it. A fact, known to fisher- 

 men, and poor who use them for food, is, that they 

 are more easily collected in the night-time than in 

 * Johnston, "Int. to Conchology," p. 328. 



