88 Our Food Mollusks 



On the southern and eastern coasts, a very small 

 oyster, possibly a variety of O. cucullata, grows in great 

 numbers in the shallow waters of bays and inlets. The 

 shell rarely attains a length of more than two inches. 

 This oyster encrusts the rocks between tide lines, and 

 cannot be removed without breaking the shell. Trie 

 fishermen therefore go among the rocks at low tide, and 

 open the oysters without attempting to detach them. 



Another distinct species, Ostrea gigas, an extremely 

 large and heavy form, is found in a few localities on the 

 Japanese coast. It seldom occurs in very shallow waters, 

 where other oysters are commonly found, but at a depth 

 of ten or twelve fathoms. Though this oyster is used 

 for food, it is so rarely taken that it does not often ap- 

 pear in the market. Its habit of life in deep water per- 

 haps has made its culture impossible. 



Because the habits of all oysters are very similar, the 

 methods employed in rearing the Japanese oyster, though 

 entirely independent in origin, are essentially like those 

 of Europe and America. In the Inland Sea, as else- 

 where, oysters require for the process of reproduc- 

 tion the comparatively fresh waters of bays receiving 

 streams from the land. On the Japanese coast, as in 

 Europe, localities having waters of the optimum density 

 are limited in area and more or less narrowly defined. 

 At certain points, however, it is possible for the culturist 

 to obtain his own set of young, and rear them for mar- 

 ket on a single small plot of bottom which he has 

 rented. In Europe it is almost everywhere necessary 

 for him to purchase his young oysters from another 

 who possesses ground on the very few bottoms favorable 

 for oyster reproduction. 



Japanese culturists have not adopted the tile collector 



