PROPAGATION OF THE MOLLUSCS. 165 



every field and garden ; hosts of Limnaese people every pond ; 

 and the sea absolutely swarms with molluscs which either graze 

 upon the submarine pastures, or, warring upon each other, serve 

 in their turn as food to countless enemies. Animals generally 

 so defenceless, and exposed to so many persecutions, must neces- 

 sarily multiply in an analogous ratio. The calamary produces 

 from forty to fifty thousand eggs in a single season ; a thousand 

 garden slugs are capable of rnultiplying in one year to the 

 number of five hundred millions ; and the oyster lays several 

 millions of eggs in the course of the summer. The germs of a 

 new generation become more numerous as the means of defence 

 are smaller ; and thus we find the sedentary and helpless mussels 

 more prolific than the cephalopods, which have been so admira- 

 bly equipped both for defensive strategy and for offensive 

 warfare. 



