41 



eies are of special iiiteiTst (p. (14 ). .,Die Thiere kiiiuien bechnitende 

 vertikale Wanderunwn unterneiiincn, uamentlieh suehen sie im 

 ypatherbst die Tiefe und koninien im Friihlini; wieder herauf; ira 

 iSommer sind die .lunueu hauptsachlich in den obereu, erwarmteii 

 Hchichten /.u findeu. wiiiirend die altcron oft in dei' Tiofe umher- 

 schwimmen." 



I have also noticed the vertical ..wanderiuijs" and I believe 

 that we hei-e have a very important factor to deal with. 



For it will probably be jiroved that the movements of herrings 

 ai'e ati'ected by the vertical alterations in the places where C', fin- 

 marchicm is to be found at dittei'ent times of the year. 



Tt will be seen in my plankton-tables too that this species 

 in the winter shows itself in the upper layers of water, quite 

 thinly spread in the surface layers, while the majority is in much 

 deeper water. But some exceptions from this state of thing's have 

 been noticed, and these deserve attention. For instance, on Janu- 

 ary •24th 1899, there were quantities of these animals at Kvænan- 

 gen no deeper than — 5 meters, and the same was seen to be the 

 case on the 27th of the same month in the same year in the inner 

 iialf of the Lyngen Fiord. To this striking biological phenomenon 

 a parallel peculiarity is e\idenced in the physical conditions of the 

 layers of water, these being altogether unvarjing both with regard 

 to temperature and sahnity (ef. nrs. 145—154, 155—162). 



And in this fact there seems to lie an explanation for the 

 appearance of herrings at times in the winter so far up near the 

 surface in some of the northern tiords that they can be caught 

 with nets. 



To give an idea of the distrilnition of this species deeper down 

 in the winter, in those tiords into Avhich the ocean water Hows, 

 the following list of observations made is useful. Dr. Petersen's 

 closiuL'-net. with an aperture of about 0.09 sq. m. was used. 



Ciila)uis finman-liiCKs. 



1K99. I^)mbaken III. 



llnni .ilii ni 



V2 1S99. Oxsund. 



Bottom 630 m. 



These figures speak for themselves. In February 1899 the 

 numbei' of C', finmarehims reached the maximum at a depth of 

 200— .300 m. 



It will also be seen fiom these observations that in the 

 Avinter a really considerable immbei' of this important plankton 

 form may be found in the basins of the fiords, as that it may truth- 

 fully be said that there is food there for eventual winter herring 

 shoals. 



Again it will be noticed on reference to the table dealuig with 

 Oxsund {'V2 1899), that C'. /?)M)««rc/iic!(s is only found very spar.sely 

 distributed at the gi-eater depths of 400—600 m. Tliis is still 

 further emphasized in the following figui'es. 



is'.cj. Oioti 



llottdni .'jrid in. 



Bottom 258 m. 



Bottom 640 m. 



