OYSTEKS. 365 



to be their only sense, and that is placed in the tentacles of the 

 mouth. 



The mode of reproduction in these creatures is very peculiar. The 

 oyster unites in itself the functions of both sexes. In the same organ 

 are found the eggs called spat and the mobile corpuscles intended 

 to fertilize them. 



The eggs are yellowish in colour, and exist in prodigious numbers 

 in each individual. We are assured that an oyster may carry as many 

 as two millions of eggs ! Nature always makes ample provision for 

 the preservation of species ; but in spite of the most ample provision 

 here displayed, man, in his reckless and wasteful gluttony, has all but 

 defeated Nature. A tyro can compute how many individuals a bank 

 of oysters reckoned at twenty thousand would produce, at the rate of 

 two millions, or eight hundred thousand, as other authorities assert, 

 from each one annually, and it will amount to an incredible number 

 in fact, each would multiply itself by millions in three years ; and yet, 

 thanks to our improvident management, they get scarcer every year. 



The spawning season is usually from the month of June to the end 

 of September : during this season the oysters deposit their eggs in the 

 folds of the mantle. During the period of incubation the eggs remain 

 surrounded by mucous matter, which is necessary to their develop- 

 ment, the whole having the appearance of a thick cream this milky 

 appearance being due to the accumulated mass of ova surrounded by 

 the mucus : this mass undergoes various changes of colour while losing 

 its fluidity, becoming successively yellowish, greyish, brown, and violet, 

 a condition which indicates the near termination of the embryo state, 

 for the oysters do not, like many other inhabitants of the sea, leave 

 their ova ; they incubate them in the folds of their mantle, and only 

 discharge them when they can live without the maternal protection. 

 Nothing is more curious to witness than a bank of oysters at the 

 spawning season. Every adult individual of which it is composed 

 throws out its phalanx of progeny. A living dust is seen to exhale 

 from the oyster bank, troubling tKe water and giving it a thick cloudy 

 appearance, which disseminates itself little by little in the liquid, until 

 it dissipates and loses itself far from its focus of production. The spat 

 is soon scattered far and wide by the waves ; and unless the young 

 oyster finds some solid body to which it can attach itself, it falls an 

 inevitable victim to the larger animals which prey upon it. In 



