THE OYSTER. 



419 



in based on those characteristics which in his own judgment are most valuable. 

 In the arrangement, however, which has been followed in these pages, the bivalves are 

 divided into two sections, founded on the presence or absence of the siphons through 

 which the water passes for the double purpose of creating the blood, and supplying the 

 digestive organs with the necessary fooa. In the first section, termed Asiphonidae, 

 are included those bivalves in which the siphons are wanting. 



I\ the first family of which the common OVSTER is a very familiar instance, the two 

 valves are unequal in size, and the animal inhabits the sea. The oyster is too well 

 known to need description , but it may be mentioned, that practical naturalists have for 



CHINESE WINDOW. -Placuaa placenta. SADDLE SHELL. Anomla ephlpplum. 



LONG-HINGED OYSTER. -Ostrea Canadensls. 



some years been carefully studying its habits, for the purpose of breeding the valuable 

 mollusc artificially, and so of securing a constant supply throughout the four months 

 of the year during which the creature is out of condition. In this country the system 

 is being gradually carried out, but in France it is developed to a very large extent, and 

 with great success. 



The details of the process are too elaborate to be here described, but the general 

 idea may be given in a few words. The very young spawn, or " spat," as it is techni- 

 cally named, is removed from the natural beds, and is dispersed in shallow " banks," 

 so that each tiny Oyster has plenty of room, and can affix itself to the bed of the bank 

 without being injured by the pressure of its fellows. Fascines, made of slender branches, 

 and sunk into banks paved with stone, birch, and broken earthenware, are found to be 

 most useful for this purpose. In the banks near Dieppe, the Oysters are seen lying in 



