138 EDIBLE BRITISH MOLLUSCA. 



carry the seed of oysters is a well-known fact, since 

 the walls of sluices newly erected are often covered 

 with them. In the island of Re the existence of oyster- 

 beds, however, no longer depends upon this contin- 

 gency, they being now in a state of permanent self- 

 reproduction. Again, in some localities it is sufficient 

 to prepare the emerging banks for collection, to see 

 them soon covered with seed ; but in other places 

 nothing would be obtained without transplanting 

 proper subjects. The concession of emerging banks 

 is anxiously applied for by the inhabitants of the coast, 

 — the more so, as improvements in the working of this 

 branch of trade are of daily occurrence. Thus, Dr. 

 Kemmerer, of Re, covers a number of tiles with a 

 coating of a kind of mastic, brittle enough to enable him 

 to detach the small oysters from it. When this coating 

 is well covered with seed, he gets it off all in one piece, 

 which he carries to the place where the seed is to 

 grow. The same tile he coats a second time, and so on." 

 In France, oysters having a green tint are con- 

 sidered great delicacies, and the art of greening 

 oysters is carried to the greatest perfection on the 

 coasts of Aunis, whence come the celebrated green 

 oysters of Marennes. They receive their colour and 

 peculiar flavour when transplanted to certain beds or 

 claires, which, at the approach of winter, are lined with 

 a kind of vegetation, which disappears in the spring ; 

 and the oysters are said to owe their colouring to the 

 absorption of the chlorophyl with which the waters 

 of the claires are saturated. It is a fact that the 

 oyster assumes its green colour when the claire grows 

 green, and loses its colour when the claire is deprived of 

 its vegetation. Some have thought that the greening 



