26 The Under-Water World 



wastage. It is estimated that in un- 

 protected areas only one oyster out of 

 every two million eggs attains maturity. 

 Fish may contain and lay an enormous 

 number of eggs. Day has estimated 

 that a ling contained 160,000,000, and 

 this was for many years regarded as the 

 piscine record until J. Schmidt, a few 

 years ago, counted 300 million eggs in 

 the ovaries of a large sun-fish. The cod 

 lays over 9,000,000 eggs, the angler fish 

 and plaice 1,000,000. Such figures may 

 well impress one not only with a sense 

 of precautions taken by Nature to ensure 

 the continual existence of these creatures, 

 but also with a realisation of the terrific 

 odds against any individual egg ever 

 hatching, and having hatched, surviving 

 to maturity. It has been calculated 

 that if every oyster born during a period 

 of ten years could be guaranteed to sur- 

 vive all dangers, the river mouths would 

 be choked and the sea-bed piled to a 



