March 8, 1877] 



NA TURE 



413 



its ancient origin and close alliance with the organic remains 

 preserved in the fossiliferous strata from the close of the Second- 

 ary period. First of all may here be named a fine, probably 

 new Crinoid, over a span long, which was here obtained in 

 numerous living specimens, and which shows an unmistakable 

 resemblance to a few of the oldest fossil forms of this, in our time, 

 almost extinct animal group ; next a very peculiar and interest- 

 ing holothuroid animal, colossal chalk sponges, and large num- 

 bers of a new and very peculiar Pycnogonide, also a remark- 

 able blood-red coloured Crangon (Rwke) with integuments thin 

 as paper (Ilymenocaris), besides several lower Crustacea, for the 

 most part new ; the mollusc commonly occurring here is that 

 which is so characteristic of our older glacial clay, the Siphono- 

 dentaliiun vitreuin, M. Sars, which on our coast is first found 

 living in the most northerly part of Unmark. The fauna in these 

 great depths, though peculiarly interesting, both with reference 

 to zoology and geology, appears however as a whole to be rather 

 poor and without variety. The contrary is the case where the 

 bottom begins to rise towards the sea banks. Here we find at a 

 depth of 400 to 900 fathoms, but still within the cold area, an 

 uncommonly abundant and varied animal life. Quite contrary 

 to what we might be inclined to expect from the prevailing low 

 temperature, so far is there from being any trace of hindering or 

 preventing the development of animal life, in comparison with 

 our coast fauna, that we find the rather as we go downwards an 

 exceedingly remarkable luxuriance in the development of the 

 fauna expressed both in the numerous and varied animal forms 

 occurring here, and in the comparatively colossal dimensions 

 which several of these here reach ; indeed, one of the marine 

 animals taken up here, belonging to the Umbellularia, had a 

 length of quite eight feet. From the specimens which we got 

 up with the help of dredges, trawl-nets, and swabs, we have been 

 able, if only approximately, to form a sort of idea of the peculiar 

 physiognomy which the sea-bottom here presents. 



Forests of peculiar Cladorhiza, with tree-like branches, here 

 deck the bottom for long stretches. Between the branches sit 

 fast beautiful medusa heads (Euryale), and variegated^a'r-j/;>r«^r 

 (Antedon), and variou; Crustacea, among them the marvellous 

 object, Arcturus Baffin!, known from the Polar Sea, and slow- 

 moving Pycnogonida, partly of colossal size (up to a span between 

 the extremities of the feet), creep along between their branches 

 and with the help of their enormously-developed proboscis suck 

 out their organic juices ; a whole world of more delicate plant- 

 like animals (Polyzoa and Hydroida) having at the same time 

 fixed their dwellings on the branches and stems of the sponges 

 when dead and deprived of their organic bark substance. In 

 the open spaces between the sponge forests creep along beautiful 

 purple sea-stars (Astropecton) and long- armed Ophiurids, together 

 with numberless Annelids of various kinds, and round about 

 swarm different sorts of Crustacea, lonij-tailed, bristly Decapoda 

 (Crangon), finely-formed Mysida (Eyrthrops, Panerythrops, 

 Pserdomma), masses of Amphipoda (Anonyx), and Isopoda 

 (Munnopslda). Above all project, like high mast timber in a 

 coppice, the predominating Umbellularia with their delicate 

 straight stems and elegantly- curved crowns set full of fringes of 

 polyps. The light of day does not, properly speaking, pene- 

 trate to these great depths, but as a compensation there is pro- 

 duced, by the animals themselves, a splendid illumination of the 

 whole, inasmuch as almost all are strongly phosphorescent, or 

 have the power to produce from their bodies an intense light, by 

 turns bluish, greenish, and reddish. 



So often as our bottom-scraper or trawl-net found bottom in 

 that region which, after the animal type that was undoubtedly 

 the most prominent and characteristic, we named the region of 

 the Umbellularia, we were certain to have a rich zoological 

 prize, and the day was indeed in most cases unfortunately quite 

 too short for the proper examination and preservation ot all 

 those treasures fetched up from the depths of the sea. 



Higher up, in a depth of 3C0 to 100 fathoms, and at a dis- 

 tance from the coast of from ten to twenty Norwegian miles 

 (about 70 to 140 English), begins that extensive barrier which 

 forms, as it were, the foundation on which our land rests, and 

 by which the cold Polar Sea depths are shut off from it. This 

 barrier begins in most cases with a hard, stony bottom, so that 

 our dredgings were here attended with great difficulties. Nume- 

 rous rolled stones, whose smooth rounded forms and worn edges 

 clearly enough show that they had at one time been subjected 

 to the powerful action of ice, lie here strewn on the sometimes 

 very uneven bottom, consisting of solid rock, and prevent the 

 dredge from acting properly, or fill up its mouth so that only in- 

 complete specimens of the animal world living here can be 



obtained. The fauna has here quite altered its character, and 

 more resembles that common on our coasts ; but it appears to 

 be a rule that below this point at the border of the barrier 

 it is considerably richer than that nearer the shore, a fact which 

 also stands in full agreement with the long known great abun- 

 dance of fish at these places. 



When we finally survey what here can only in a general way 

 be pointed out concerning the physical and biological relations 

 of the tract of sea we traversed we may, both in a physiographic 

 and a zoological respect, divide the depths of the sea surround- 

 ing our country into two regions differing greatly in character, 

 namely, the warm and the cold areas. The first occupies the 

 whole Skagerak and the North Sea, and farther north the sea 

 along our coast to a distance of ten to twenty Norwegian miles, 

 including herein all the fiords cutting deeply into the land, and 

 stretches towards the north to the northernmost point of Fin- 

 mark. The cold area commences where the bottom begins to 

 sink from the sea-banks towards the great deeps lying beyond 

 them, and towards the south reaches nearly to the latitude of 

 Stadt, and towards the south-west extends in the form of a nar- 

 row wedge in between the Fajroe and the Shetland Islands as 

 far as the 60th degree of latitude. Towards the north the cold 

 area extends to the Pole, which properly is its central point. 

 We have examined it at one of the points where it extends 

 farthest to the south, where it has shown itself to be everywhere 

 very sharply and distinctly defined from the warm area. As we 

 proceed farther north, the boundary between the two becomes 

 less distinctly marked, inasmuch as the cold area little by little 

 raises itself from the depths, until in the Polar Sea it finally 

 rises to the surface, and thus also occupies the littoral region, 

 the warm area being at the same time greatly diminished in ex- 

 tent. The close correspondence with the above-described pecu- 

 liar physical conditions in the sea surrounding our country has 

 been to a very considerable degree explained by the experience 

 obtained during our expedition, and thus a very important con- 

 tribution has been m.ade to the meteorology of the sea in general. 

 A fuller explanation of these purely physical phenomena is also 

 of the greatest importance to us zoologists for the right under- 

 standing of the different biological conditions in the sea ; but as 

 such an explanation belongs properly to the physical-meteoro- 

 logical researches, I will not here enter farther upon it, but keep 

 to the more purely zoological side of the matter. 



With regard to the character of the fauna in the cold area, it 

 is purely arctic or glacial without any southern mixture whatever ; 

 and we have already been able to identify several of our species 

 with types before collected in the Polar Sea during the various 

 North Polar expeditions fitted out in Sweden, Germany, England, 

 and America. In higher latitudes those animal types, which in 

 that part of the sea which we examined are only found below the 

 400 fathoms' line, live in comparatively shallow bands, indeed even 

 in the upper stratum of the sea, which interesting fact appears 

 still further to confirm the view held by several men of science 

 that the distribution of animal life in the sea is mainly dependent 

 on temperature, depth having only a comparatively limited in- 

 fluence upon it. The purely Arctic fauna which prevailed on our 

 coasts during the Glacial period, and which has left behind its 

 traces in the glacial clays and in the older glacial shell banks, has, 

 under altered meteorological conditions, little by little drawn 

 down to the depths, where the effect of these conditions was less 

 sensible, while the places which it inhabited have been occupied 

 by more southern, immigrating types. At great depths in our 

 fiords which run far into the land, a remnant of the original 

 Arctic fauna has been able to maintain itself. But this is clearly 

 only a fortuitous circumstance, as clearly enough appears from 

 the generally small size and stunted appearance of these animal 

 types, and their complete extinction is probable. This we are 

 now, after having acquired an accurate acquaintance with the 

 temperature of the sea, able to explain on purely physical 

 grounds. For even to those deep pools in our fiords the influ- 

 ence of the milder climatic conditions has at last reached, so that 

 at depths of 650 fathoms there is a temperature of 6" C, which 

 may be supposed to have a prejudicial influence on the growth 

 of these types. On the other hand, the temperature off our sea- 

 banks at a much smaller depth remains unchanged, such as it 

 was in the Glacial period, both here and close to our coast, and 

 therefore we find also here, even at a remarkably southern lati- 

 tude, no impoverished and stunted, but as luxuriantly developed 

 an Arctic or glacial fauna as high up in the_ north in the Polar 

 Sea. 



The very important light which from the side of meteorology 

 may be thrown on several yet obscure phenomena in the deve- 



