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November, must use for their development, viz. half a year*); for we can 

 scarcely imagine that all these early eggs are destroyed if they are not car- 

 ried outside the Skaw to seas where perhaps the development can take place 

 without being hindered by temperature or ice as in our shallow waters, for 

 instance to the western shores of Jutland or such places where there is 

 very little ice**). When we see that the eggs which are floating in the 

 Baltic Sea and have been fertilized there, and which Hensen as we know 

 has often found in great numbers, are scarcely hatched there, except per- 

 haps quite exceptionally, then we cannot help fancying this second possibility. 



It has long been supposed that most eggs of plaice which flow fertilized 

 about in the water, must be destroyed; but it has been supposed also, 

 perhaps, that most of them were destroyed by other animals, which eat them. 

 It is my conviction, however, that the physical conditions here play an 

 exceedingly important part, and this is particularly conspicuous if we try 

 to imagine how all the larval fish which have come out of the eggs are to 

 reach the shore; for, they must either be able to hasten on their develop- 

 ment from pelagic animals to animals that live on the bottom when carried 

 to the shore by a fortunate current, or they must sink to the bottom when 

 it is required by their development. Those which sink down too far from 

 the shore must be destroyed, for no small plaice are found on the deep. 

 Those only which sink to the bottom near the shores will be kept alive, 

 and when we remember the area of the bottom, the volume of the waters, 

 and the distribution of the eggs, we see that they, certainly, form but a very 

 small fraction of the whole number of larval fish. 



That these little, c. 10 mm long, animals, should actually immigrate to 

 the shores is here looked upon as unimaginable. 



In the winter-months I have repeatedly looked for the little plaice 

 (the 0-group) at places where they were found in autumn but always with 



Comp. Schi0dte's evidently false supposition concerning this matter. 

 Among the flat-fishes I have examined, and whose fry I have proved to live 

 in our seas," it is only the plaice that requires such a long time to pass through 

 its pelagic stage, or rather, it is only the plaice that requires such a long 

 time between the beginning of the breeding-season and the first appearance 

 of the fry on our shores; for the spawning-season of Flew, flesus is much later 

 (the early spring-months), and yet its fry appears on the shores scarcely a month 

 later than that of the plaice. 



The fry of Rhombus Icevis & mdximus and of Solea vulgaris, whose spawning- 

 time is still later, on the borders of spring and summer (May — July), appears already 

 on our shores in the months of July and August. 



Of Flew, limarida I know too little as yet to be able to give the precise data, 

 but it seems also to follow the rule, that the nearer the warm season the spawning- 

 season falls, the shorter time passes before the tender fry is seen on the shores. 



