3S6 THE FLOUNDER FAMILY. 



to young flounders in the harbour. At ebb-tide in May this 

 bird watches by the side of the tiny pools in the mud, and 

 seizes a young flounder whose prominent glistening eyes 

 (minute though they be) are sufficient to betray it although 

 its almost transparent body is immersed in the sand. It then 

 lays it on the side of the pool and watches for another, and 

 so on until it has a fair mouthful to carry to its young 1 ." 



Throughout the summer shoals of these little flounders 

 are found in the sandy shallows. Some of them attain a 

 length of 3 inches by the end of June, and may have a 

 maximum age of 4 months, but may be less, while in July 

 they may be as long as 4 inches. By the autumn many may 

 attain a length of as much as 3|- inches. In the tanks at 

 Plymouth Cunningham found they grew from ^ an inch to 

 3 inches in 3^ months. Before this time the characters of the 

 adult are assumed and with them, no doubt, the adult habitat, 

 but the subsequent history is little known, though in the tanks 

 of the Plymouth Laboratory they grew to 7 inches in 18 months. 



The flounder is undoubtedly more shore-loving than the 

 plaice, and is often found far up the estuaries of rivers, 

 apparently being in no way inconvenienced by the change in 

 the salinity of the water. Essentially a dweller in mud or sand 

 it buries itself till only its keen little eyes are visible, the 

 general colour of the body completely harmonising with its 

 environment. Its love of fresh water is remarkable, and one 

 cannot help conjecturing as to how far the flounder would 

 become adapted to a river-life had nature not placed a 

 barrier in its way in the form of a pelagic spawning- 

 habit. It is evident that no fish with freely floating eggs 

 can become of completely fresh-water habitat for at every 

 generation the helpless embryos would be borne backwards to 

 their original home in the sea, even assuming that the difficulty 

 with regard to specific gravity were overcome. It is not 

 therefore surprising to find that all fresh-water fishes, as far as 

 is known, have demersal eggs. (Cf. Shad.) As regards the rate 

 of growth, more data are required before pronouncing with any 

 degree of certainty upon the length attained by a young 

 1 W. C. M. 6th S. F. B. Ee.pt., p. 274. 



