240 CUTTLE-FISH, MOLLUSC A, ETC. 



mon mussel (Mytilus edulis) is one of the most fertile 

 of all mollusca, and this natural history fact has 

 been turned to greater practical account off the French 

 coasts than off our own. It is capital food, especially 

 when fresh, and as such is cultivated off the Nor- 

 mandy coasts, as we cultivate oysters, and thence im- 

 ported into the interior in immense quantities as food 

 for the working people. Off the Norfolk coasts the 

 mussel banks which form there so rapidly are used 

 chiefly for manuring the land. The so-called " moss" 

 is in reality the byssus, or anchoring threads, and has 

 nothing poisonous about it, although this part has 

 been credited with producing the painful affection 

 known as " musselling." We believe, however, that 

 the latter is due to partaking of decomposing mussels, 

 some of which are apt to get into every measure of 

 them, from the way some of the fishmongers have of 

 mixing up their old stock with the new. In this way 

 a very old and rotten specimen may be made to taint 

 and infect all the rest during the process of boiling 

 and preparing for the table. 



Oysters are never likely to lose their interest to 

 people who care anything at all for the pleasures 

 of the table ; and our aquaria have already con- 

 tributed some important facts concerning oyster 

 culture. Apart from their well-known and highly- 

 esteemed edible qualities, they are favourites with 

 managers of large marine aquaria from their useful- 

 ness in clearing turbid sea water, and rendering it 



