240 



O. Nordgaard. 



ami it will be interesting to see what other animals exist together 

 with Lophohelia. But first 1 will mention a few facts about the 

 coral itself. This easily recognized species has been found in several 

 of the fiords on the west coast of Norway up to the Vest Fiord. 

 in rather deep water (about 150—500 in.). As far as I know, 

 my specimens have been taken at the most northerly place for this 

 species (Tranodybet, the Tys Fiord I). And I am inclined to think 

 that no living specimens will be found farther north, as the colonies 

 live on our coast under unusually uniform and settled natural con- 

 ditions, with a temperature of (3—7° C. and a salinity of about 

 35 %o. There is reason for supposing that at Verrill's locality 

 ..ntt' Nova Scotia" the conditions are similar. At any rate, Verrill 

 (1. e. p. 506) mentions that off Cape Sable the temperature, at a 

 depth of 65—131 fathoms, varies between 42" and 40" Fhr. 

 (5°.5— 8° ('.). CI', stations nr. 2065—2071. The bottom at a 

 couple of these stations is given as being of coral. It is, therefore, 

 probable that the temperature here too is near 6—7° C. at those 

 places where Lophohelia prolifera occurs alive. According to Verrill, 

 only dead specimens were taken at 1060 fathoms, and if it be 

 remembered that in the Norwegian waters the coral in question 

 does not extend beyond the boundary of the ocean water, it tempts 

 me to conclude that the species cannot live at a depth of 1060 

 fathoms off Nova Scotia, notwithstanding that the fall in temperature 

 is not particularly great. Verrill (1. c. p. 503) says ..The bottom 

 temperatures betweeu 1000 and 2 000 fathoms were usually between 

 37° F. and 39" F.. and rarely 40°." If Lophohelia from 1060 

 fathoms had existed at this place under present natural conditions. 

 it ought therefore also now to be able to thrive in a temperature 

 of 3—4° C. But the investigations hitherto made in Norway seem 

 to contradict this possibility. A couple of suggestions may be made 

 to account for the occurrence of Lophohelia at such a great depth. 

 The colonies may have been transported from some other locality, 

 so that when the dredgings were made from the „Albatross" they 

 were in a secondary layer, or a fall in the bottom level may have 

 taken place. There are instances of a rise of the bottom in a 

 couple of places in Norway where Lophohelia has been brought 

 several meters higher than the present water level. 



Prof. Michael Sars 1 ) was the first who discovered Lophohelia 

 prolifera at a height of 30 meters above sea level, this was at 

 Drobak in the Kristiania Fiord, he paid great attention to this 

 occurrence and gave a iiood description of it. Later on, more light 

 has been thrown upon the subject by Prof. W. C. Br0gger,'-') who 

 writes in part as follows : - - „From the time of the deepest sub- 

 mergence of the Kristiania region, an epiglacial fauna is known, 

 which has lived at a great depth, at least 150 meters. This is 

 the famous dead coralreef at Drobak, south of Kristiania, where 

 the shore, from 60 meters below the sea-level to about 30 meters 

 above it, is covered with the remnants of a great reef of Lophohelia 

 prolifera." Br0gger also shows the height of the reef above the 

 sea-level (30 m.) + the minimum depth of the coral in the present 

 fiords (150 m.) answers to the upper marine boundary at Drobak 

 (180 m.) - - „a proof, that the Lophohelia-reet was formed, partly 

 at any rate, during the deepest submergence of the land at Drobak." 

 A similar argument holds good with regard to the other occurrence 

 at Stenk.per at the end of the Trondhjem Fiord. 



J ) Fossile dyrelevninger fra ciuartserperioden, p. 76 — 77. 

 -) Om de senglaciale og postglaciale niveauforandringer i Kristianiafeltet. 

 N. G. U. No. 31, p. 182—187, p. 689 (English Summary). 



Natural conditions at the time when Lophohelia lived at Drobak 

 and Stenkjaer cannot have been very different to what they are 

 now in the deep western fiords, and it may from this be concluded 

 that the Gulf Stream, at least from the epiglacial time, tilled the 

 channels and basins in the Norwegian fiords with its warm water. 



Together with Lophohelia, M. Sars found various other cha- 

 racteristic forms, e. g. Pecten vitreus, P. aratus, Lima excavata, 

 Area nodulosa etc. 



These animals very frequently follow Lophohelia in our fiords 

 at the present day, but in no definite state of dependence. Further, 

 the presence of these animals proves that the natural conditions in 

 the depths of the fiords during the epiglacial time could not have 

 been so very dissimilar to the present conditions. But, on the 

 other hand, the deposits in the shallow waters plainly show that 

 in the upper layers of water, quite a different state of things was 

 prevalent to that of the present day. 



It is interesting to give a list of the most important animals 

 which have been observed together with Lophohelia at the most 

 northern localities where this species has been found. 



3 % 1900, Arno, 300—400 m. 

 Lophohelia prolifera. Pall., Paramuricea placomus, Fix.. Ophia- 

 cantha spectabilis, G. 0. Sars, Flustra barleei, Busk, Limn excavata, 

 Fabr., Lamellaria latens, 0. F. Mull., Pandalus propinqvus, G. 

 0. Sars. Pontophilus norvegicus, M. Saks. 



'" :; 1899, Tranodybet. 450—530 m. 

 Lophohelia prolifera, Pall., Ophiacantha spectabilis, G. ( >. Sars, 

 Pteraster militaris, 0. F. Mull., Pandalus propinqvus, G. 0. Sars, 

 Hippolyte polaris, Sab., Galathodes tridentatus, Esmark. 



2 7s 1899, The Tys Fiord I, about 500 m. 



A sounding at the beginning of our dredging stated a depth 

 of 725 m. and at the end 50<> m. We drove along very quickly, 

 however, and our line was hardly long enough, so that we got 

 nothing from the clay at 725 m. It was first at the edge that 

 the trawl began to take in anything, and when we drew it up 

 from a depth of about 500 meters, the net was half full of living 

 and dead branches of Lophohelia, on which was found: — 



Pulvinulina punctulata, D'ORb. 



There were also: — 



Lophohelia prolifera, Pall., Protanthea simplex, Garlg., Opliia- 

 cantha spectabilis, G. O. Sars, Ophioseolex glacialis, Mull, and 

 Trosch., 0. purpureas, Dub. and Kor., Pteraster militaris, 0. F. 

 Mull., Echinus elegans, Dub. and Kor., Lineus cinereus, Punnett, 

 Leodice norvegica, Lin., L. gunneri, Storm, Terelrratulina caput- 

 serpentis, Lin., Waldheimia cranium, Mull., Lima excavata, Fabr., 

 Pecten vitreus, Chemn., Pleurobranchus plumula. Mont., Metopa 

 alderi, Bate, Janira maculosa. Leach., Pun/lulus propinqvus, G. 

 0. Sars, Hippolyte polaris, Sab., Galathodes tridentatus. Esmark, 

 Munida rugosa, G. 0. Sars, M. tenuimana, G. 0. Sars, Ciona 

 intestinalis. Lix. 



Some of the species mentioned have here their northern limit, 

 e. g. Protanthea simplex, Echinus elegans, Lima excavata, Gala- 

 thodes tridendatus. A wide distribution southwards has for instance 

 Galathodes tridentatus, which, according to Milne-Edwards and 

 Bouvier, extends right down to the west coast of Marocco, and 

 Lima excavata, of which Friele and Grieg write in their account 

 of the Mollusca of the Norw. North Atlantic Exp.: — „It is also 



