S3 6 DISCOVERY REPORTS 



The Diphyidae are also only poorly represented. A small concentration is noticed in 

 record 4, but a fairly even distribution in record 35. 



The Chaetognatha (records 4, 5, 18, 20, 27, 28, 29, 34 and 35) show on the whole a 

 continuous distribution with short-spaced fluctuations. 



The Ostracoda are only represented by one well-defined patch in record 8. 



The Copepoda are represented in sufficient numbers to chart in all records except 7 

 and 24. Marked fluctuations are the rule, and as will be discussed presently there is a 



HOUR. 



00 



01 



02 

 — I— 



-4- 



03 



— I— 



8 



23 

 — 1- 



MILES I 



c.c. 



22 "> TOTAL PLANKTON VOLUMES [except salpa] 



04 



05 



-+- 



06 



+ 



10 II 12 13 14 15 116 



I 



07 



+ 



-+- 



17 



OQ 



-t- 



18 19 



20 

 IB-I 



IB- 



14- 



PROPORTIONS OF PRINCIPAL CONTENTS ONLY ROUGHLY ESTIMATED , 



COPEPODA □ EUPHAU5IACEA JUV W L/MAONA U CHAETOGNATHA 



°ABCDEFGHJKLMNOPQ.RSTUVWXYZABCDEFGHJKLMNOPQRSTUVWXYZABCDEFG 



ABCDEFGHJKLMNOPQRSTUVWXYZABCDEFG 

 C.C ABCDEFG 



IB0 1 5MALL SALPA 

 140 



120-1 



100 

 80 

 GO 

 40- 

 20- 







-I — I — 1 — 1 — r- 



Fig. 18. Variations in the plankton, measured as volumes but omitting Salpa (S.fusiformis) shown separately, 

 taken by a series of consecutive surface tow-net hauls each towed for 5 of a mile at a speed of 2 knots. The 

 relative volumetric proportions of the predominant plankton forms: Copepoda, Euphausiacea juv., Limaana 

 and Chaetognatha are shown for each haul. For further explanation see text. 



suggestion that these fluctuations may follow in a certain rhythm, the pattern of which 

 varies on different occasions. Vertical migration undoubtedly plays an important part 

 in the variations in the numbers observed, but on top of these migrational variations 

 actual fluctuations are evident. 



Of the amphipods, young Parathemisto are alone taken in sufficient numbers to con- 

 sider and on only two records 25 and 26. Here the fluctuations may be due to vertical 



