15 



the western and true Baltic, when only a few determinations were made duriug 

 the absence of the Director. Eggs of the cod (Gadus cuUarias) liave always been 

 determined, when they had the embryo in any way developed. 



On account of the incompleteness with which the eggs were determined, 

 I shall restrict myself to some few remarks ou the compositiou of tlie stock of 

 pelagic eggs in Danish waters and refer for the rest to Tab. 1 and tlie snmmary 

 from this: Tab. 2. 



During the first months of the year the eggs which occur are almost 

 exchisively withont oil-globules. In January 1904 we have only found eggs of 

 plaice, in March also those of cod, long-roiuili dah and flonnder-dah, all without oil- 

 globules, and in addition single small eggs with oue or several brownish oil- 

 globules, which we have determined as those of the rocldinfj'''. Long-rough dab 

 eggs were only found in March, plaice and cod eggs right to April and May, 

 rockling eggs still in June, and flouuder-dab eggs in all montlis from March to 

 August. 



In the summer, from May and June on, most of the species of pelagic 

 eggs have one or more oil-globules. We have only determined a few species with 

 oil-globules, namely: solp, dragonet and in single cases maclcerel, whilst with regard 

 to the preseuce of the eggs of the rhomhoids, gurnards and others we have been 

 content with suppositions, but I have paid uo attention to these in workiug out 

 the tables. Of the eggs without oil-globules occurring in the summer months, in 

 addition to the fiouuder-dab, we have only determined those of the sprat. These 

 are however very commou; in 1904 they were found in the months April — August. 



Pelagic yonng from species witli pelagic eggs. 



The young fish which are hatched from pelagic eggs are not restricted in 

 the same degree as the eggs to water-layers of a certain salinity; yet, during the 

 first period of development especially, they will remain in the water-layers where 

 they are hatched. The influecce of currents on the pelagic eggs is thus continned 

 on the pelagic young; and these are carried from the intermediate regions either 

 outwards towards the North Sea or inwards towards the true Baltic. It is only 

 where the salt water ou account of the configuration of the bottom is somewhat 

 stationary, that the pelagic young like the pelagic eggs are saved from beiug carried 

 away. In the intermediate parts of the Danish waters therefore, we find but few 

 piaces, chiefly in the western part of the wester Baltic, where a large number of 

 the pelagic young of species with pelagic eggs are to be met with. In searching 

 for the great mass of these young we must folio w the currents which carry away 

 the eggs, thus, both the surfacecurrent out towards the North Sea and the bottom- 

 current in towards the true Baltic. We have for example actually found these 

 young in the Skager Rak in great numbers (see Tab. 1), but neither in 1904 nor 

 in earlier 3'ears have we found the pelagic young of pelagic eggs in the true 



* Some of the eg^s we have determined as rockhng belong perhaps in reality to the 

 forkbeard (Ranice2is raninus), the adult of which is occasionally taken in Danish waters, e. g. in 

 the Little Belt. 



