88 PENNATULIDA. 



given') in Grieg's review (Berg. Mus. Aarb. 1891) must be reduced to the following: Pennatula 

 phosphorea, Penn. aculeata, Penn. grand is, Virgularia affinis, Virg. mirabilis, Virg. cladiscus, Stylatula 

 (Dubenia) elegans, Pavonaria finmarchica, Halipteris christii, Protoptilum thomsoni, Funiculina qua- 

 drangularis, Kophobelemnon stelliferum, Umbellula encrinus. 



From the Fseroe Islands, Iceland, and Greenland no Pennatulid was hitherto known 

 (apart from Umbellula lindahli and the statement concerning Pavonaria finmarchica, see p. 39). It has 

 now been proved that several species are found in the depths of the sea near these countries, also a 

 few in more shallow water. From the banks at the Fseroes are now known Pennatula grandis 

 (numerous) and Halipteris christii. From more shallow water (less than 100 fathoms) at Iceland (the 

 Vestman Islands) are now known: Pennatula pliosphorca (var. Candida), Virgularia mirabilis, Virg. 

 cladiscus, and Stylatula (Dubenia) elegans. From the fjords of the Fseroes and Iceland — in contrast 

 to those of Norway - - sea-pens are now as little known as hitherto. This holds good also with 

 regard to the western fjords of Greenland. From the sea between Greenland and the American 

 polar islands only Umbellula lindahlii was previously known; this species has now been found again 

 farther south , in the Davis Straits, and to it are further to be added Pennatula aculeata, Penn. 

 prolifera, Authoptilum grandipZorum, Distichoptihim gracile, and Kophobelemnon stelliferum, so that for 

 the present six species of sea-pens are known as « West-Greenland: species. From East-Greenland 

 only one species, Umbellula encrinus, is known, and only from its northern part. 



The fact that the species upon the whole divide into an Atlantic and an Arctic territory seems 

 to me, however, of greater interest than the reference of the species found to the fauna of the nearest 

 land. The boundary between these regions is very far from coinciding with the purely geographical 

 boundary of the Polar Circle between the Atlantic and the Arctic Oceans; it is contingent upon the 

 configuration of the bottom and the influence of this upon the temperature and currents of the sea. 



I have previously (Geograf. Tidsskrift, vol. 14, 1896 — 98, p. 38, and Forhdl. 15 Skand. Natur- 



forskaremote i Stockholm 1898, pp. 271 — 74) tried to show that the submarine ridges connecting 



Greenland with Iceland, Iceland with the Fseroe Isles, and these with the Scottish Isles, form a 



boundary between an Arctic and an i\tlantic deep-sea fauna; on the one hand, they prevent directly, 



by their height, the wanderings of many forms, that is to say forms that may be supposed always 



and in all ages to be confined to depths greater than 300 fathoms; on the other, they influence the 



distribution of animals by producing a great climatic contrast in the sea-water and by deflecting the 



currents. North of the ridges the temperature of the water from the bottom to about 300 fathoms 



below the surface is constantly below zero, whilst south of the ridges it is always positive. The cold 



northern basin forms part of a large and deep polar water which spreads farther north beyond the 



large land-masses of the northern hemisphere, but in other places is also shut out from other ocean 



depths by ridges or regions of more shallow water (Smith Sound etc., and the Behring Straits); the 



deep, warm waters occurring south of the ridges pass evenly into the great depths of the true 



Atlantic, only forming the northern part of this Ocean; west of Greenland it passes far north right 



through the Davis Straits and even some way into the Baffin Sea, constantly with positive bottom 



') This account contains 30 species; but Leplopiilum gracile K611. var. norvegica Dan. Kor. has already been abandoned 

 by <",rieg himself as a young stage of Funiculina quadrangularis. Comp. p. 50. The account also, at the time it appeared, 

 should have contained 31 «species», as Koren's & Danielssen's Cladisczis Kollikeri has been forgotten. 



