72 



DISCOVERY REPORTS 



significant difference in the numbers of a species in two samples will be great enough 

 to swamp any minor inaccuracies which might arise from the methods of working the 

 net and analysing the catch. At the same time conclusions must be drawn with caution, 

 and the character of the plankton in a locality must not be judged from a single haul. 



ORGANISMS IDENTIFIED 



Samples taken by the N ioo B in the Antarctic contain a relatively small number of 

 species, the majority of which are easily recognized. It is therefore possible for a single 

 worker to familiarize himself with the common species and work straight through the 

 samples, avoiding the delay which would be involved if all the catches were sorted and 

 the groups distributed to a number of experts for separate identification. I have, how- 

 ever, received much assistance from Mr F. C. Fraser, formerly of the Discovery staff 

 and now on the staff of the British Museum, and from Dr H. E. Bargmann, Mrs 

 M, E. White and Mr A. H. Laurie, of the Discovery staff, each of whom has undertaken 

 the analysis of a number of the samples. The Copepoda from some of the samples were 

 identified by the late Dr Andrew Scott, who has also furnished a valuable reference set 

 of named specimens. Other named specimens have been provided, of Amphipoda by 

 Dr Barnard of the South African Museum, of Siphonophora by Capt. Totton of the 

 British Museum, of Polychaeta by Mr Monro of the British Museum, and of Pteropoda 

 by the late Miss Massy. Capt. Totton and Mr Monro have also kindly given me personal 

 assistance from time to time. Under the guidance of Dr Kemp I have been able to 

 identify the various species of Enphausia. 



Even with such assistance it has not been possible throughout to identify by any 

 means all the species which occur, but I have attempted to estimate the number of the 

 following in every sample. 



Siphonophora. 

 Diphyes antarctica, Moser. 

 Dimophyes arctica, Chun. 

 Pyrostephos vanhoffeni, Moser. 



Medusae. 



Sibogita borchgrevinki, E. T. Browne. 

 Solmnndella sp. 



Polychaeta. 



Tomopteris sp. (large). 

 Tomopteris sp. (small). 

 Vanadis antarctica (Mcintosh). 



ECHINODERMATA. 



Auricularia antarctica, MacBride. 



Copepoda. 



Calanus acutus, Giesbrecht. 

 C. propinquus, Brady. 



Copepoda (cont.). 



C. simillimus, Giesbrecht. 

 Rhincalanus gigas, Brady. 

 Pleuromamma robusta (F. Dahl). 

 Metridia gerlachei, Giesbrecht. 

 Haloptihts occllatus, Wolfenden. 

 Haloptihts sp. 

 Parenchaeta sp. 

 Heterorhabdus sp. 

 Encalanus sp. 

 Euchirella sp. 

 Candacia sp. 



Amphipoda. 



Parathemisto gaudichaudi (Guerin). 

 Primno macropa, Guerin. 

 Vibilia antarctica, Stebbing. 

 Eusirus antarcticus (Thomson). 

 Cyllopus spp. 



