4 THÉEL, PR1APUI.IDS AND SIPUNCULIDS OF THE SWEDISH ANTARCTIC EXPEDITION 1901 — 1903. 



The distinguished investigator of the oceans, Sir John Murray, 1 pronounces 

 his opinion with regard to the deep and shallow-water faunas of the Kerguelen region 

 of the great Southern Ocean in the following manner: »In the reports of the specialists 

 who have examined the collections from Kerguelen and other islands of the Southern 

 Ocean, very frequent reference is made to the identical or closely allied species which 

 occur in the cold waters of the Northern and Southern Hemispheres, but have not 

 as yet been recorded from the intervening tropical regions, either in shallow or in 

 deep water. If there be, as indeed seems to be proved by the following investiga- 

 tions, very few widely distributed, or rather universally distributed, species in the 

 deep-sea, and if there be a large number of identical or closely allied species in the 

 colder water of the two hemispheres, wholly separated from each other by the tropics ; 

 if in short, the marine faunas towards either pole are genetically more closely related 

 to each other than to any intervening fauna, tlien we are face to face with one of 

 the most remarkable facts in the distribution of organisms on the surface of the 

 globe. A study and comparison of Arctic and Antarctic marine faunas and floras 

 seem indeed to lead directly to very important suggestions as to the past history of 

 the earth and the gradual evolution of the physical and biological conditions which 

 now prevail över its surface.» 



The fauna and flora of the great Southern Ocean evidently exhibit features of 

 the highest interest, widely separated as they are from the arctic seas. 



Before proceeding to set forth my own thoughts of the m ätter in question, I 

 may remind the reader of the fact that there are other distinguished investigators 

 who entertain an opinion differing from that of Sir John Murray. Thus, e. g., 

 D'Arcy W. Thompson 2 accentuates his doubts in pronouncing the following views: 

 ». . . . It has been maintained by some that this latter is the case; that there is a 

 common bipolär fauna non-existent in the tropics, and even that hundreds of species 

 in the Arctic and Antarctic fauna are identical one with another. This view is con- 

 tested by others, and I for my part do not share it. But on this question more 

 arguments is mucli less to be desired than more investigations. For, even supposing 

 the specific identity of so many forms to be disproved, it may be there remains 

 sufficient ground for a similar deduction from the general affinities of the rest: or, 

 on the other hand, if the inference be wholly false, we may find resemblances which 

 are not original, but which throw light on questions of variation and evolution under 

 similar conditions. » 



I understand quite well Thompson's caution in expressing this views. In con- 

 formity with many other investigators he is in doubt whether there really exist similar 

 species in the two polar seas but which are lacking in the intervening regions. I 

 quite agree with him when he says: »But on this question more arguments is much 

 less to be desired than more investigations.» That was just my intention when I 

 began to work out this report. For I thought that every recorded instance of iden- 

 tical bipolär species, non-existent in the tropics and subtropics, would be of value 



1 Tians. Roy. Soc. Edinburgh. Vol. 38. Pari II. 189G. 



- The Antarctic .Manual fm- the use of the Expedition of 1901, edited by George Murkay. London 1901. 



