DISTRIBUTION AND HYDROLOGY 49 i 



The collections also comprised material from localities outside the Antarctic and 

 sub-Antarctic areas, as follows : 



Cape Verde Islands 



Bugula dentata 

 Ascension Island 



Aetea curta 



Scrupocellaria frondis 



South Africa 

 Menipea crispa 

 M. triseriata 

 Bugula calathus 



QUEENSCLIFFE JETTY, PORT PHILLIP, VICTORIA 



Scrupocellaria ornithorhyncus 

 Scruparia ambigua 

 Aetea anguina 



New Zealand 

 Amastigia harmeri 

 Menipea zelandica 

 M. vectifera 

 Tricellaria monotrypa 

 Emma triangula 



New Zealand (cont.) 



Scrupocellaria ornithorhyncus 



Canda arachnoides 



Caberea boryi 



C. helicina 



C. darwinii (minima-type) 



C. glabra 



C. angusta 



C. rostrata 



Synnotum aegyptiacum 



Cornucopina zelandica 



C. moluccensis 1 



Beania discodermiae 1 



B. pulchella 



B. intermedia 1 



Bugula expansa Hastings (1939, p. 338) 1 



B. cucullata var. cuspidata 



Caulibugula tuberosa 



Dimetopia cornuta Busk (1852a, p. 384) 1 



Scruparia ambigua 



Some of these species are also known from the sub-Antarctic region, namely, Aetea 

 curta, Scrupocellaria ornithorhyncus, Caberea darwinii, C. rostrata and Scruparia ambigua 

 (see Table 3, p. 479). 



THE RELATION BETWEEN HYDROLOGICAL CONDITIONS AND 

 THE DISTRIBUTION OF THE SPECIES 



The outstanding feature of the foregoing discussion is the correlation of the distribu- 

 tion of the species with hydrology. The abundant collections of specimens, and the fine 

 and comprehensive analysis of the hydrology provided by the Discovery Investigations 

 give an unusual opportunity of testing this relationship. My results are, for reasons 

 explained on p. 477, incomplete and tentative, but I think they are very suggestive. 



Among the Antarctic and sub-Antarctic Cellularine Polyzoa we have several instances 

 of apparent correlation : 



(1) The decisive influence on the non-abyssal fauna of the change in hydrological 

 conditions at the Antarctic convergence which is demonstrated by Table 3 (p. 479). 



(2) The presence of a fauna with Antarctic affinities in a zone off the Patagonian shelf 

 probably influenced by Antarctic water, demonstrated in Table 4 (p. 487). 



(3) The possible relation of the distribution of the abyssal species to the warm and 

 cold deep currents (p. 486). 



On the other hand, the fauna of Heard Island is similar to that of the other islands 

 n the South Indian Ocean despite its different hydrological conditions (see p. 483). 



In the distribution of plankton the very close correlation with hydrological conditions 

 is well known, and, among free-swimming animals, the distribution of the fishes has 

 been found to correspond very closely with the temperature of the water (Norman, 193 1 , 



1 Collected by the Terra Nova Expedition, not obtained by the 'Discovery'. For those not discussed 

 elsewhere in this report a reference is given. 



