i6 



DISCOVERY REPORTS 



micro slide. Each larva was placed on the slide with the tail projecting into the angle, 

 and was held up by the sides of the trough so that the total length from tip of rostrum 

 to end of telson could be read quickly. The measurement of adolescents was done 

 directly on a scale marked off in 0-5 mm. divisions. 



A difficulty was encountered as a result of the preservation of the specimens. The 

 greater mass of the material was preserved in formalin, but nearly all the samples taken 

 by the 'William Scoresby' were in 70 per cent alcohol. A comparison of specimens 

 preserved in alcohol with others from the same stations preserved in formalin showed 

 that a considerable shrinkage had taken place in the specimens kept in the former fluid. 



Table II 



The actual figures are expressed in Table II. In order to make the specimens more 

 nearly comparable as regards length the factor i -09 was employed and records of length 

 of spirit-preserved larvae were multiplied by it to bring them into line with the rest of 

 the measurements. 



ACKNOWLEDGMENTS 



Whilst the work on this paper was in progress Dr Rustad published a paper on 

 " Euphausiacea, with notes on their biogeography and development" (1930), and 

 another "On the Antarctic euphausiids from the Norvegia Expeditions, 1929-30 and 

 1930-31 " (Rustad, 1934). Dr Johan T. Ruud (1932) also published his paper " On the 

 biology of southern Euphausiidae ". I wish to make full acknowledgment to both of 

 these authors for the use I have made of their publications, which are constantly referred 

 to here. 



Acknowledgments are due to Dr S. W. Kemp, F.R.S., for much helpful criticism and 

 advice, to Dr W. T. Caiman, C.B., F.R.S., to my colleague Mr D. Dilwyn John and 

 former colleagues Dr N. A. Mackintosh and Dr H. E. Bargmann for the assistance they 

 have given me. I am also greatly indebted to Mr G. E. R. Deacon for his valuable help 

 where hydrographical problems were involved. 



