372 



DISCOVERY REPORTS 



PLANKTON SPECIES EXAMINED IN 80 ° W 

 In a previous paper on the Antarctic macroplankton (1934, p. 97) I gave a list of 

 species arranged in order of the abundance in which they occurred in the i-m. oblique 

 nets. Table II here shows the relative abundance of macroplankton species taken in the 

 N 70 V in 8o° W. Those species which could be identified with some confidence are 

 separated from the more doubtful species. This list differs from the previous one in 

 several details, principally because the plankton population in 8o° W differs in some 

 important respects from that of the south west Atlantic from which the material in my 

 previous paper was mostly drawn. Some differences are also due to the smaller capacity 

 of the N 70 V to catch the larger organisms. In Table II also the different species of 

 Chaetognatha are distinguished, while in the old list they were not. It must further be 

 remembered that we are dealing here with the plankton from all depths between the 

 surface and 1000 m. ; but although in the deeper hauls we find a higher proportion of 

 species which do not occur in the Antarctic surface water, the bulk of the macroplankton 

 is still made up of species which are commonly taken in the 1 m. nets hauled in the 

 upper layers. 



Table II. Relative abundance of species in 8o° W. 



Showing total numbers taken in all N 70 V samples 



Rhincalanus gigas 

 Enkrohnia hamata 

 Calanus acutus 

 Pleiiromamma robusta 

 Sagi/ta maxima 

 Sagilta gazellae 

 Sagitta planctonis 

 Dimophyes arctica 

 Parathemisto gaudichaudi, juv. 

 Conchoecia hettacra 

 Primno macropa, juv. 

 Enkrohnia hamata f. antarctica 

 Haloptilus oxycephalic 



17784 Parathemisto gaudichaudi , adult 



1 24 1 4 Calanus propinquus, adult 



9091 Primno macropa, adult 



1566 Euphausia triacantha 



963 Euphausia vallentini 



560 Euphausia frigida 



370 Clione antarctica, large 



268 Haloptilus ocellatus 



258 Auricularia antarctica 



234 Diphyes antarctica 



221 Sibogita borchgrevinki 



196 Vanadis antarctica 

 57 



Small Calanoids 

 Clione antarctica, small 

 Conchoecia symmetrica 

 Conchoecia antipoda 



Identification doubtful 



14992 Spongiobranchaea australis 



227 Solmundella mediterranea 



133 Cleodora sulcata 



127 



Only genus identified 



43 

 42 

 38 

 28 



28 

 20 



7 



5 

 2 

 2 

 1 

 1 



4 1 



16 



6 



