162 UTILIZATION OF MINUTE LIFE. 



their species can often be determined by the form 

 and colour of their shells. 



^ :jc ;fc * * 



I shall now turn to the Bivalve Mollusca, as 

 examples of which the Oyster and the Mussel may 

 be taken. 



The common mussel (Mytilus edulis), which lives 

 in the sea, and is quite distinct from the fresh- 

 water mussel, of which I shall speak further on, is 

 found on our coasts in considerable quantities, and 

 also upon the rocky coasts of almost the whole of 

 Europe. These mussels live fixed to the rocks or 

 piles, to which they attach themselves by means of 

 their byssus, a sort of silky hair which the animal 

 secretes for this purpose. In some genera allied to 

 mussels, such as the Pinna of the Mediterranean, 

 this byssus attains a foot and a half in length, and 

 the inhabitants of Palermo sometimes use it to 

 make gloves and stockings. Its chemical nature 

 does not appear to have been examined. 



At certain seasons mussels are extensively con- 

 sumed as an article of food, for which purpose they 

 have been actively cultivated. For many years they 

 have been bred artificially in salt-water marshes 

 that are periodically overflowed by the tide, the 

 fishermen throwing them in at the proper seasons. 

 The animals, being undisturbed by the agitation of 

 the sea, and protected from the inhabitants of the 



