LISTS OF SPECIES BY STATIONS 



135 



Station 118 

 July 5, 1929; 42° 29' N, 155° 24' E; bottom depth, 5404 m; 24 species 



Depth of tow, m 

 Temperature, °C 

 SaHnity, 0/00 

 \olume of tow, cm' 







25.8 

 8.21 

 1.4 



50 

 26.5 

 8.21 



1.3 



100 

 27.0 

 7.94 



1.4 



Acrocalanus gracilis 



Bathycalanus rigidus 



Calanus finmarchicus 



hyperboreus 



Calocalanus pavo 



Clausocalanus arcuicornis. 

 Clytemnestra rostrata. . . . 

 Eucalanus attenuatus 



crassus 



elongatus 



Euchirella brevis 



Lucicutia clausii 



Lucicutia flavicornis. . . . 

 Macrosetella gracilis. . . . 

 Metridia longa 



lucens 



M icrosetella rosea 



Oithona attenuata 



setiger 



similis 



spinirostris 



Oncaea minuta 



Paracalanus parvus 



Pseudocalanus minutus. 



The surface temperature was 5° lower than at the pre- 

 ceding station and fell 4° in the 100 meters; the salinity 

 remained practically the same, but the hydrogen-ion con- 

 centration diminished at the 100-meter level. Calanus 

 finmarchicus was the only species found in the surface tow; 

 13 species were found in the 50-meter tow, and 21 in the 

 100-meter tow. Thirteen species (54 per cent) were each con- 

 fined to a single depth and no species was found at all three 



depths. The numbers of both species and individuals are so 

 small as to make it evident that the bulk of these northern 

 tows is made up of other constituents of the plankton. The 

 two deeper tows contain the only record for Bathycalanus 

 rigidus. Corycaeus and Farranula entirely disappear and do 

 not reappear until at station 130, and Oncaea is reduced to 

 a single species. Oithona yielded 4 species but none of them 

 were in the surface tow. 



Depth of tow, m 

 Temperature, °C 

 Salinity, 0/00 

 X'olunie of tow, cm' 



.Station 119 

 July 7, 1929; 45° 24' N, 159° 36' E; bottom depth, 5198 m; 16 species 



50 100 Depth of tow, m 



6.9 3.0 1.6 Density (o-,p I 25.8 



32.9 33.0 ii.I Hydrogen-ion cone. (pH) 7.96 



31 31 62 Length of tow, miles 1.3 



50 



26.6 

 7.92 

 1.3 



100 

 27 

 7.85 



1.4 



Acrocalanus gracilis 



Calanus cristatus 



hyperboreus 



Clausocalanus arcuicornis. 

 Eucalanus elongatus 



subtenuis 



Macrosetella gracilis 



Metridia lucens 



M icrosetella rosea 



Neocalanus gracilis 



robustior 



Oithona attenuata 



similis 



Paracalanus parvus 



Pseudocalanus minutus. 

 Scolecithricella porrecta. 



The surface temperature was the lowest for the entire 

 cruise and fell almost 80 per cent in the 100 meters; the 

 salinity was also low and increased slightly, and the h>drogen- 

 ion concentration diminished. Two species were found in the 

 surface tow, 9 in the 50-meter tow, and 14 in the 100-meter 

 tow. Nine species (56 per cent) were each confined to a 

 single tow and 2 were present in all three tows. Although 



the temperature at the 50-meter le\el was only 3° and at the 

 100-meter level 1?6 above the freezing point, all the species 

 except 2 had retired to the lower levels. This indicates that 

 even a temperature which is very close to freezing is not an 

 effective deterrent to negative phototropism. Aversion to 

 strong light is more powerful than to low temperature, and 

 the downward migration occurs regardless of temperature. 



