CHINESE WINDOW. Placuna placenta, 



SADDLE-SHELL. Andmia ephippium. 



LONG-HINGED OYSTER. Ostrea 



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 food. In the first section, termed Asiphonidas, are included 

 those bivalves in which the siphons are wanting. 



IN the first family of which the common OYSTEE 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 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 ; .dea 

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

 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 regular rows 



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