882 THE FLOUNDER FAMILY. 



majority spawned in water of from 4| to 10^ fathoms. As 

 the adults are essentially estuarine in their habits, there is 

 a migration in connection with spawning, from the fresh or 

 brackish water to the areas a few miles offshore where spawn- 

 ing is effected. 



Again, it is said, there is a migration of flounders into 

 deeper water during the cold of winter, which is of course 

 not connected with the spawning function (Buckland). Further 

 observations, however, are needed on this head, for our own 

 do not bear them out. 



As in the case of the plaice there have been some curious 

 mistakes made concerning the eggs of the flounder. Buckland 

 states that the masses of eggs belonging to certain worms, 

 found between tidemarks, were believed by the fishermen of 

 Morecambe Bay to be those of the flounder, and Mr Cun- 

 ningham observes that the fishermen of Essex also considered 

 them to be the eggs of the plaice, as late as 1893\ 



Flounders are peculiarly susceptible to a diseased condition, 

 consisting of whitish masses of a tumour-like nature. These 

 have been construed by the fishermen of some districts as the 

 eggs of the flounder, adhering to the skin of the parent. They 

 have been studied at St Andrews^ by several observers, and 

 one of these (Mr Sandeman) claimed that their inner structure 

 resembled that of certain types of eggs, although there was 

 of course no possibility of their being those of the flounder, as 

 these had already been fertilized and described by Dr Malm, 

 of Goteborg, in 1868, and the early stages of development 

 fully worked out in 1884 at the St Andrews Marine La- 

 boratory. 



The egg hatches eleven days after fertilization in March, 

 but in the warmer month of June the period of incubation 

 is reduced to about six days. In the former case, the de- 

 velopment of the embryo proceeds till the fifth day without 

 any sign of pigment or opacity. By this time however a 

 number of yellowish-brown spots make their appearance, a 



' Marketable Marine Fishes, 1896, p. 230. 



'' See W. C. M. Ann. Nat. Hist. June, 1885, and Srd Rept. S. F. B., p. 66, 

 1885. 



