DISCOVERY REPORTS 

 4 



THE ANTARCTIC FORAMINIFERAL FAUNA 

 The foraminiferal fauna of the Antarctic, especially when unaffected by external 

 influences, as appears to be the case in the Weddell Sea, is limited in both genera and 

 species, and primitive in nature, being principally Arenacea. In this respect it is very 

 similar to the fauna of the deep sea in all latitudes of the great oceans, many of the 

 Antarctic species being truly cosmopolitan, and others represented in the deep sea by 

 closely allied forms. Whether the deep sea was populated by migration from cold polar 

 waters, or conversely whether the Antarctic fauna had its origin in the deep sea, is a matter 

 for conjecture. On the evidence afforded by the Discovery material, supplemented by 

 the records of the ' Scotia', ' Terra Nova' and ' Gauss', I am personally inclined to the 

 view that the Antarctic fauna originated in migration principally from the deep water 

 of the adjacent oceans, and that the invasion is still in active progress. With the exception 

 of a limited number of species which appear to have a circumpolar distribution, and are 

 not found in the deep sea of warmer latitudes, I think the present Antarctic fauna 

 represents the successful attempts at the colonization of a fresh area. The conditions 

 of life have not favoured the development of the porcellanous and hyaline forms to the 

 extent which they have attained in the shallow waters of temperate and tropical seas, 

 and with few exceptions these forms play only a secondary part in the Antarctic. 



For the purpose of comparison of the faunas of the widely differing regions covered 

 by this report, the area was subdivided as follows, working westwards: 



I. WEDDELL SEA 



Sts. WS 552, 553, 555.1 



The primitive nature of the Weddell Sea fauna is well illustrated by the few soundings 

 received. All species are arenaceous except single starved specimens of Cassiduliiia, 

 Globigerina and Globorotalia, and most of them are of cosmopolitan distribution. But 

 the material received was insufficient for any general deductions, and must be considered 

 in connection with Pearcey's records from this region. Many fossil Globigerinae were 

 found at St. WS 555 (see p. 22). 



IL SOUTH SANDWICH ISLANDS 

 Sts. 363, 365-7, 369. 



The residues from this area are largely scoriae and volcanic ash, and as a result all the 

 Arenacea are very dark in colour. Foraminifera form only a small proportion of the 

 residues but are varied in species. Specimens are few in number, except in the case of 

 Miliammina and some other forms, mostly cosmopolitan. A few species were recorded 

 which are either confined to this area or much rarer elsewhere, e.g. Ophthalmidiiim 

 inconstafts, Pilulina arenacea, BotelUna goesii, Trochammina grisea, Cassidulina lens, 

 Elphidium magellanicum. There are not many species indicative of Pacific influence, 

 but among them may be reckoned the Opthalmidiiim and Elphidium, also Sigmoilina 

 obesa and Ehrenbergina pupa. 



' Full details of the stations will be found on pp. 26-44. 



