98 



RATE OF GEOWTH OP SOME SEA FISHES 



of size in one year's growth. But these specimens were not ripe, 

 and the proportion of specimens of this size is so small, that I think 

 it may fairly be concluded that the flounder does not breed at the 

 end of its first year. Of course, it is possible that the largest 

 specimens one year old breed, while the smaller are still sexually 

 immature ; but the evidence of my captive specimens is against this. 

 It seems probable, therefore, that the flounder does not begin to breed 

 until it is two years old, when its length would probably be from 

 7 to 9 or 10 inches. The largest flounder observed by Dr. Fulton 

 was 16^ inches long. The increase in length per annum must of 

 course diminish with every year of age, even if the rate of increase 

 in weight were to remain uniform, simply because the weight is 

 proportional to the cubic dimensions of the fish, and probably the 

 rate of increase in weight also diminishes with age. Therefore, a 

 flounder from 12 to 16 inches in length is in all probability at least 

 three years old and may be many more. 



Pleuro7iectes flesus, the Flounder. Specimens obtained from the Sea. 



The data here are very insufficient, and I hope to add largely to 

 their number in future. But I think it is evident that the flounders 

 taken on April 8th, 1891, in the Cattewater, were just over one year 

 old, and had grown to about the same size as the larger among the 

 specimens kept in our tanks. It seems, therefore, that the growth 

 of this species observed in captivity does not differ very much from 

 that of specimens living in freedom. Whether in a state of nature 

 specimens ever reach such a small size in one year as the smallest 

 of my captive specimens I am as yet unable to say. But it must 

 be remembered that the competition for food in a small tank con- 

 taining a large number of specimens is very great, so that indivi- 

 duals which possess a little superiority in size and activity to start 

 with, probably increase that superiority continually by seizing the 

 greater part of the food before the smaller ones can get it. No 

 doubt there is competition in the natural state, but at any rate the 



