6 



families are again divided into a great number of sub-families, whereas the 3rd 

 only includes a single such sub-family, and the 4th only 2. The disproportion of 

 this classification is very obvious. In my opinion the number of true families 

 accepted by Dr. Giesbrecht is much too small in proportion to the numerous 

 Calonoid genera established, and I have therefore felt justified in raising the several 

 sub-families to the rank of true families, though some of them, it is true, are 

 rather closely allied. I think that thus a more uniform and convenient arrange- 

 ment of the genera may be obtained. 



As the very great majority of the Calanoida are pronouncedly pelagic 

 animals, often occurring in the open sea at a considerable distance from the coast, 

 the limits of the fauna-domain ought in this case to be considerably more ex- 

 tended than is generally allowed for the bottom-forms. I therefore refer to the 

 Norwegian fauna all forms that have been found anywhere in those parts of the 

 Ocean surrounding the Norwegian coast, viz.. the Skagerak, the North Sea, that 

 part of the North Atlantic generally termed the Norwegian Sea. and bounded on 

 the west by the Shetland Isles, Iceland and Jan Mayen, and on the east by 

 Spitsbergen and Bear Island, and finally the Barents Sea, which washes the 

 greater part of the Finmark coast. Indeed, any form that has been observed 

 even at the outer limits of these parts of the Ocean, may be assumed occasionally 

 also to occur in the immediate neighbourhood of the Norwegian coast. 



Though the distribution of some Calanoid species has proved to be 

 extraordinarily wide, we must, I think, admit that several of the forms found 

 off the Norwegian coast , are of true arctic origin, others peculiar to the North 

 Atlantic, and others again of still more southern rise ; for it is very likely that 

 northern forms may occasionally be carried far away from their true home by 

 currents, and, vice versa, southern forms may be carried in the same manner 

 northwards, beyond the limits of their true domain. It may thus easily happen 

 that species of very different origin may be found in the very same tract of the 

 Ocean, though perhaps at different seasons of the year. In the great depths of 

 the Norwegian fjords, a peculiar Calanoid fauna was long ago proved to occur. 

 By the recent investigations of the plankton-organisms taken during Nansen's Polar 

 Expedition, it has been ascertained by the present author that the greater number 

 of these peculiar deep-water Calanoids are of true arctic origin, the same species 

 occurring also in the Polar basin, often at the very surface of the sea. They 

 must accordingly be regarded as relict arctic forms, existing in the depths of 

 the fjords from ancient times (the glacial period), when the sea surrounding the 

 Norwegian coast still exhibited a purely arctic character. 



