178 WILD LIFE AT HOME. 



upon which they live by a number of brown silken 

 threads of great strength.- I found one some time 

 ago an inch in length attached to a stone, and, 

 with a view to testing the stability of its anchor 

 chains, secured a spring balance, and tying a 

 piece of string round the mussel suspended the 

 whole. The stone weighed two pounds, and weight 

 was added up to four before the silken threads 

 gave way. Even then it must be borne in mind 

 that, owing to the peculiar shape of the object I 

 had to attach my string to, equal strain could not 

 be placed upon each thread at the same moment. 



The illustration on the next page, of a typical 

 bit of beach at the head of a Shetland Voe, shows 

 cockle shells both full and empty, a worm casting, 

 and other signs of life and death. Some popular 

 books of natural history say that the cockle when 

 lifted out of its home in the sand has the power 

 to bury itself again or shift to new quarters, but 

 the Scottish Fishery Board does not entirely endorse 

 these views. Some years ago the fishermen of Mid 

 Yell used to rake the sand at the head of the Voe, 

 take what cockles they required for bait, and leave 

 the rest, which, instead of burying themselves, died 

 upon the sand ; and this deplorable waste went on 

 until bait for line fishing at sea became so scarce 

 that the authorities had to step in and regulate the 

 destructive method of dealing with it. 



Periwinkles, limpets, and other mollusca abound 

 on rocky shores, and although at first sight 



