THE OYSTER. 75 



enemies and accidents at the time when it is most 

 helpless. The oyster of Northern Europe lays from 

 one to two million eggs, while our oyster lays about 

 ten times as many, but the protection which is 

 afforded to the young European oyster by the shell of 

 the parent more than balances the greater birth-rate 

 of our oyster. 



The most critical time in the life of the American 

 oyster is undoubtedly the time when the ^^^ is dis- 

 charged into the water to be fertilized, for the chance 

 that each ^%^ which floats out into the bay to shift for 

 itself will immediately meet with a male cell is very 

 slight, and infinite numbers of eggs are lost from this 

 cause. The next period of great danger comes as the 

 little embryos begin to swim and crowd to the surface 

 of the water. They are so totally defenseless and are 

 so close together that a little fish swimming along 

 with open mouth may swallow thousands in a few 

 mouthfuls, and I have found that at this time a sudden 

 fall of temperature is fatal to them, and a cold rain may 

 destroy millions. As soon as they are safely past this 

 stage and have scattered and begin to swim at various 

 depths, their danger from accidents and enemies is 

 greatly diminished, and their chance of reaching ma- 

 turity increases rapidly. Experiments which I carried 

 on many years ago show that there is no difficulty in 

 rearing them up to this point in captivity, and that in 

 a very small aquarium millions of them may be safely 

 carried past the most precarious part of their lives 

 and freed from their greatest dangers. 



Although the mortality at their early stages is so 

 excessive, the number of young oysters which pass 



