254 



DISCOVERY REPORTS 



Table XLIV 

 The depth distribution of Thysanoessa vicina, males, as shown by the 



Table XLV 



The depth distribution of Thysanoessa spp., females, as shown by the 

 N 70 V nets for stations of 500 m. depth and over 



PATCHINESS IN DISTRIBUTION 



It is essential to know whether the nets used at any station in a survey give fairly 

 representative samples of the quantities of different organisms in the surrounding waters, 

 or whether the unevenness in the distribution of these organisms may not make the 

 samples unrepresentative. In the present survey we have evidence on this point from 

 two sources : firstly, in regard to the larger forms from two series of consecutive net hauls 

 made with the N 100 H nets at Sts. 150 and WS 53, and secondly, in regard to the 

 smaller forms, by comparing the repeated observations taken at St. 41. The Continuous 

 Plankton Recorder, an instrument partly designed for the purpose of studying the 

 patchiness in the distribution of the plankton, was only in the experimental stages in 

 this commission and was not used in the actual South Georgia survey, so that a discus- 

 sion of the results obtained with it, having little bearing on this actual survey, will be 

 reserved for a later paper which is in preparation. The results from a single record, 



