376 



NOETH SEA INVESTIGATIONS. 



It appears that the male is mature at from 12 to 15 inches^ as in 

 the turbotj but probably some smaller specimens^ if procurable, 

 would be found mature. 



The margin of variation in the size at which the female first 

 spawns appears to be rather more narrow than in most other 

 species ; but it was impossible to obtain small females in sufficient 

 numbers. 



Spawning period. — Spawning appears to commence in the latter 

 part of April, and becomes general by the beginning of May. It 

 is continued throughout that month and the early part of June, 

 after which it diminishes, and is practically over by the end of July. 

 The spawning period is thus much the same as that of the common 

 sole. 



Plaice {Pleuronectes platessa) . 

 From February to June, the larger fish chiefly during the spawning 



season. 



The occurrence of a ripe male at 6 inches is probably altogether 

 exceptional, 15 inches appearing to be nearer the usual size at 

 which the male becomes mature, but I did not pay very much 

 attention to this sex during the spawning season. 



At 17 inches the proportion of mature females is much greater 

 than shown above, as in selecting fish of this size for examination I 

 have picked out those which seemed likely to prove immature 

 Conversely, at sizes less than 1 7 inches, those which appeared to 

 be mature were selected. 



At 18 inches I have seen in the market numbers of evidently 



* Nearly ripe, ripe, or spent, except f ^^ which the reproductive organs very little 

 advanced. 



