EUPHAUSIACEA AND DECAPODA LARVAE 



Table XXXIV 

 The depth distribution of Thysanoessa jurcilia as shown by the N 70 V nets 



223 



It is seen clearly that the species belongs to the cold polar layer ; these figures should 

 be compared with the charts of temperature and salinity in Figs. 7 and 8. The 

 figures have been divided into those taken in daylight and those in darkness, and in 

 almost every case a striking increase is shown in the night figures for the top 250 m. It 

 has frequently been suggested that the phenomenon of vertical migration is not a real 

 one, and that the results obtained are due to the organisms avoiding capture by the nets 

 during daylight. These figures would at first sight appear to support this, but on being 

 further considered in the special section on vertical migration on pp. 244-250, where we 

 come to the conclusion that this apparent effect is due to the results of both shallow and 

 deep-water stations being here combined together. 



The complete record of the occurrence of adult and larval forms is given in the tables 

 in Appendix II. 



Decapoda Larvae 

 Decapod larvae, at present unidentified, were taken at the following stations: 



It is hoped that they will later be reported upon together with other Decapod larvae 

 taken over wider areas by the Discovery investigations. 



