412 



NATURE 



{March 8, 1877 



servators of the Zoological Museums, the Directors of the Zoo- 

 logical Gardens, and several lecturers on zoology and botany at 

 the High Burghal Schools, 



Accept, then, Sir, on your sixty-ninth birthday, this testimony 

 of regard and esteem, not for any value it can have for you, but 

 as a proof, which we are persuaded cannot but afford you some 

 satisfaction, that the seeds by you so liberally strewn have also 

 fallen on fertile soil in the Netherlands. 

 We are, Sir, &c., 



The Directors of the Netherlands 

 Zoological Society, 

 (Signed) President, A. A. van Bemmelkn 



Secretary, H. T. Veth 



The following is Mr. Darwin's reply :— 



Dozun, Beckenham, February I2 



Sir, — I received yesterday the magnificent present of the 

 album, together with your letter. I hope that you will endea- 

 vour to find some means to express to the 217 distinguished ob- 

 servers and lovers of natural science, who have sent me their 

 photographs, my gratitude for their extreme kindness. I feel 

 deeply gratified by this gift, and I do not think that any testi- 

 monial more honourable to me could have been imagined. I am 

 well aware that my books could never have been written, and 

 would not have made any impression on the public mind, had 

 not an immense amount of material been collected by a long 

 series of admirable observe/'S, and it is to them that honour is 

 chiefly due. 



I suppose that every worker at science occasionally feels de- 

 pressed, and doubts whether what he has published has been 

 worth the labour which it has cost him ; but for the remaining 

 years of my life, whenever I want cheering, I will look at the 

 portraits of my distingnished co-workers in the field of science, 

 and remember their generous sympathy. When I die the album 

 will be a most precious bequest to my children. 1 must further 

 express my obligation for the very interesting history contained 

 in your letter of the progress of opinion in the Netherlands, with 

 respect to evolution, the whole of which is quite new to me. I 

 must again thank all my kind friends from my heart for their 

 ever-memorable testimonial, and 



I remain, Sir, 

 Your obliged and grateful servant, 



(Signed) Charles R. Darwin 



THE NORWEGIAN NORTH-SEA EXPEDITION 

 OF 1876' 



Zoological Researches 

 A MONG the various scientific objects of our expedition the 

 -^ examination of the biology of those parts of the ocean 

 which we traversed was one of the most important. We had 

 with this view equipped ourselves in the best way with all 

 the apparatus required for the purpose (dredges, trawl-nets, 

 swabs, sieves, &c.), chiefly after the newest English models, a 

 considerable quantity of ropes of various kinds, and heavy iron 

 weights to hold the apparatus to the bottom were also stowed 

 away in the hold of the vessel. Tliere was besides procured a 

 large quantity of glass vessels of different sizes and kinds, 

 from small test-tubes to cylinders a foot in diameter, and a con- 

 siderable stock of spirits for preserving the specimens that might 

 be collected. 



That the zoological material that might be brought up with 

 the apparatus we have named might be arranged and the preli- 

 minary examinations made, which would be of great importance 

 for the later working out, we considered it indispensable that 

 as many zoologists as possible should accompany the expedition ; 

 we also thought it right that a skilful artist should always be at 

 hand. The zoological party consisted of Overlsege Danielssen, 

 Grosserer Friele, and myself^ and as artist we were fortunate 

 enough to engage Herr Schiertz, landscape-painter, whose prac- 

 tised pencil and keen, all-embracing faculty of observation were 

 exceedingly useful to us. There is a series of masterly-coloured 

 pictures from his hand which will be a true ornament to the 

 zoological treatises, which in course of time will be published on 

 the work of the expedition. 



The zoological work was divided in this way : — Overlsege 

 Danielssen and Dr. Koren undertook the Echinodermata, Ge- 

 phyreerna, and Corals ; Grosserer Friele, the MoUusca ; Dr. 



' By Prof. G. D. Sars. From Daghladet, January 26 and 27. 



Hansen, the Annelida ; and I myself the other classes, the Crus- 

 tacea, Pycnogonida, Polyzoa, Hydroida, Spongia, together with 

 the lowest organisms standing on the boundary line between the 

 animal and vegetable kingdoms (Foraminifera, Radiolaria, and 

 Diatomacea), and that department of the researches which even- 

 tually concerns our salt-water fisheries. We have all been occu- 

 pied for a considerable time in working out each his own portion 

 of the collected material. But as this has been extraordinarily 

 abundant, it has not been possible for any of us to bring his ex- 

 amination to a conclusion so that a detailed account of it can 

 be given. As, besides, the more special results will be reserved 

 for the collective work, which it is proposed to publish when the 

 expeditions are concluded, it will be sufficient here to state some 

 of the most important results of the expedition. It may also 

 here be mentioned that these researches, carried on far out in 

 the open sea from a comparatively small vessel, and at depths 

 approaching 2,000 fathoms, are, even under the most favourable 

 circumstances, attended with extraordinary difficulties, and oc- 

 cupy a comparatively long time. That we, notwithstanding the 

 exceedingly unfavourable state of the weather during the expe- 

 dition, were able to obtain such an abundance of zoological 

 material, is due to the skilful and intelligent way in which the 

 work was carried out by Lieut. Petersen, to whom Capt. Wille's 

 command was given over. 



During our expedition we had in all employed the dredge 

 from the vessel sixteen times, the trawl-net twelve times, 

 both these together twice, and the swabs but once ; there were 

 thus no fewer than thirty-one separate casts, and of these only a 

 few were unsuccessful, while most of them gave very satisfactory 

 results. A net was also employed for examining the marine 

 animals occurring in the upper stratum. Boat dredgings were 

 also undertaken in Sogne Fiord, at Husoe, at Thorshaven in the 

 Fteroe Islands, and in the harbour at Reykjavik. Without en- 

 tering on any detailed specification of the numerous animal forms 

 thus brought from the depths of the sea, I will merely state tliat 

 there are interesting species, new to science, of nearly all classes, 

 of which complete descriptions and drawings will by-and-by 

 be published. 



The greatest depth reached during the expedition was about 

 2,000 fathoms, almost half-way between Norway and Iceland ; 

 there were several casts at depths of over 1,000 fathoms. The 

 zoological researches were begun in Sogne Fiord, where the 

 considerable depth of 650 fathoms was reached, the greatest 

 depth which up to that time had been examined on our coasts. 

 We found here the common deep-sea fauna known from earlier 

 researches, viz., of Hardanger Fiord, and various rarities 

 were collected ; among others a well-preserved specimen of 

 the remarkable family, Brisinga, discovered by Asbjoernsen {B. 

 coronata, G. D. Sars), several specimens of the Friapuloides 

 bicaudata, Danielssen, and great numbers of the beautiful haired 

 Mimida tenuiviana, G. D. Sars, of which previously only very 

 few specimens had been found. 



Our researches, however, first attained their peculiar interest 

 when we reached the extended barrier that lies along our coast 

 on the west, the uttermost limit of which forms the so-called 

 Havbro. Here below 300 fathoms begins the yet little examined 

 cold area, with a bottom-temperature of from 0° to i "b" C, and 

 the fauna now, in correspondence with this temperature, exhibits 

 a very peculiar character, totally different from that on our south 

 and west coasts. Seventeen of our casts were in the cold area, 

 and we have thus some idea of the peculiar physical and biolo- 

 gical conditions prevailing there. 



Over the extensive depression which occupies the greater part 

 of the expanse of sea between Norway on the one side, and the 

 Fasroe Islands and Iceland on the other, the bottom below 

 1,000 fathoms appears everywhere to consist of a very peculiar, 

 loose, but very adhesive, exceedingly light, nearly greyish white 

 clay, which is very strongly calcareous, and, on being washed or 

 passed through a sieve, appears to consist almost exclusively of 

 shells of a little, low organism, belonging to the Foraminifera, 

 Biloculina. We have therefore named this deep-sea clay Bilo- 

 culina clay, to distinguish it from the kind of clay which occurs 

 in the warm area at a great depth in the Atlantic Ocean, and 

 which is called, after a very different Foraminifer, Globigerina. 

 The Biloculina clay of the cold area contains a larger quantity of 

 lime than the Globigerina clay of the Atlantic. It gives off, 

 when treated with an acid, an uncommonly large quantity of gas, 

 and when it is pressed and dried, it is converted in a short time 

 into a very hard and compact sort of limestone. We have here 

 a complete chalk or limestone formation coming into existence, 

 I and the fauna occurring here also bears a considerable impress of 



