6 G. 0. SARS. CRUSTACEA. [NORW. POL. EXP. 



them, are largely mingled with fresh water, and constantly subjected to a 

 rather low temperature, they seem in reality to offer less favourable conditions 

 for the well-being of higher organisms. I am therefore of opinion, that the bulk 

 of the pelagic animals found in the North Polar Basin are in fact derived from 

 the west through the Atlantic current flowing in beneath the superficial Siberian 

 current. On the other hand, I think that the latter is of great importance 

 in conveying a constant supply of nourishment to the pelagic animals of 

 the North Polar Basin. This nourishment consists of microscopic algae, chiefly 

 Diatomece, which are found to abound in the superficial polar water of the 

 Siberian Sea, though gradually diminishing in quantity westwards, apparently 

 owing to their being largely fed upon by the various pelagic animals. Indeed, 

 without such a constant conveyance of nourishing matter, there could be no 

 such rich animal life in the Polar Sea. 



It is a very remarkable fact, that forms which have hitherto been 

 regarded as quite southern in distribution, are also represented in the Polar 

 Sea. I have several instances of this remarkable occurrence to report on, 

 as regards the pelagic Copepoda. Thus, in a sample taken at about the 

 centre of the Polar basin traversed, I found a well preserved specimen of a 

 Calanoid, differing conspicuously in its external appearance from all the other 

 forms, and easily recognizable as a species of the genus Hemicalanus Glaus. 

 This genus has as yet only been known from the Mediterranean and the tropical 

 parts of the Atlantic and Pacific Oceans, never having been met with either 

 off the Norwegian coast or off the Atlantic coast of Europe. Furthermore, 

 in the sea north of the New Siberian Islands, two species of the genus Onccea 

 Phillipi are found in great abundance, and both these species I have been 

 enabled to identify with perfect certainty with species recently recorded by Dr. 

 Giesbrecht from the Bay of Naples. One of the species, 0. conifera Giesbr., 

 was certainly observed by the present author many years ago off the 

 south coast of Norway; but the other species, 0. notopoda Giesbr., is as 

 yet only known from the Mediterranean. In about the same tracts, in which 

 the two above-mentioned species of Onccea occurred, another very peculiar 

 Copepod, belonging to the same group, was met with. It is a species of the 

 genus Lubbockia Glaus, hitherto only known from the Mediterranean and the 

 tropical parts of the oceans. Finally, in the very same sample in which the 

 last-named Gopepod was found, I succeeded in picking up some specimens of 



