MOLLUSCA. 169 



mangrove oysters, as they hang chiefly upon the 

 root-like branches of the mangrove (Rhizophora 

 mangle), which propagates itself in an extraor- 

 dinary manner along the muddy banks of tropical 

 rivers. 



Oysters which live suspended in this manner 

 grow to a much larger size than those which lie in 

 shoals at the bottom of the sea, as we observed was 

 the case with mussels. At St. Domingo the negroes 

 cut them off with a hatchet, and they are served 

 upon the table with the roots. 



Oysters have been cultivated more or less for 

 centuries ; the ancients attached great importance 

 to this great cultivation. The Eomans cooked 

 them in a great variety of manners ; and Apicius, a 

 glutton who lived in the time of Trajan, is said to 

 have possessed a peculiar secret for fattening 

 oysters. Britain has been celebrated for its oysters 

 since the time of Juvenal. Pliny informs us that 

 Sergius Orata got much credit for his stews of 

 Lucrine oysters, "for the British oyster was not 

 then known." Among the antiquities discovered at 

 Cirencester, a Koman oyster-knife was found, and 

 presented to the British Association in 1856. 



The art of propagating these mollusca in arti- 

 ficial oyster-beds has been much perfected of late 

 years. The works of M. Coste, who has studied 

 this question in extenso on the borders of the Medi- 



