INVERTEBRATE BOTTOM FAUNA 505 



In the depression these are all common enough to be regarded 

 as an essential part of the fauna. Spatangus rascki, for 

 instance, appears never to approach the coasts or to enter the 

 fjords, but keeps to the deeper parts of the plateaus where it 

 takes the place oi Spatangus pttrpuretts ; it has also been found 

 by the " Michael Sars " on the continental slopes south of the 

 Faroe Islands. Pontaster te^iiiispimts only exceptionally enters 

 the fjords of West Norway to the south of Stat, though it is 

 found now and then in the Trondhjem fjord, and during the 

 cruise of the " Michael Sars " in 1902 it was found at the mouth 

 of the Sulenfjord near Aalesund.^ Antalis agilis and Pandalus 

 bonnieri are only met with occasionally in the fjords,^ and 

 Ulocyatlms arcticus belongs to the forms which do not enter 

 our more southerly enclosed fjords, but may be met with in the 

 more open northern fjords as far as the North Cape ; it has 

 also been found, according to Norman, on the Shetland 

 plateau. 



All or most of the forms enumerated as belonging to both 

 the fjords and the plateaus, as well as those which chiefly or 

 exclusively belong to the plateaus, may be met with as far north 

 as Lofoten, and probably extend to the North Cape. The 

 Norwegian North Atlantic Expedition came across many of 

 the forms that inhabit the Norwegian depression and fjords in 

 deep muddy hollows on the plateau north of Stat, and some of 

 the forms occur on muddy bottom upon the outer slopes of the 

 continental edge wherever the temperature is above 0° C. 



One peculiarity of the Norwegian depression still remains to 

 be mentioned, namely that a deep trench extends along the north- 

 eastern side to about the latitude of the Sogne fjord, approxi- 

 mately 400 metres deep, where experiments with lines revealed 

 a true hard-bottom fauna of corals (Paragorgia, PrijJinoa) and 

 sponges ; the "Michael Sars" found this to be the case in several 

 places in the trench.^ It is strange that this deeper portion is not 

 full of mud like the adjoining shallower parts, since usually we 

 find a reversed state of things, hard bottom rising up out of the 



^ Pontaster tenuispimis is found in two variations of colour, namely a rather pale form of 

 weak structure, which belongs exclusively to the warm area, and a deep-red form much more 

 stoutly built, which as a rule seems to belong to cold areas, though reddish individuals of weak 

 structure occur also in warmer waters. 



'^ A good many individuals of Pandahis bonnieri, which used to be regarded as rare, have 

 lately been found in the Norwegian depression and in the fjords north of Stat. It is of 

 interest to state that the Danish research vessel "Thor" has found large quantities off 

 South Iceland. It has also been discovered in the fjords near Bergen during certain years in 

 varying quantities. 



* Large well -developed colonies oi Lophohelia prolifera were found on the plateau near Stat> 

 together with other forms that are characteristic of such localities. 



