mi LI 
S GAT t.6 8 . 458 
36° Sl" Se 104° 05° W. Dec. 22, 1928 
Bottom depth 3810 m. 
Depth of tow,m. | 0 | 50 {100 |Depth of tow,m. 50 |100 
Temperature,C. }16.9j14.%/12.3|/ Density, OtP. (24.71 25 .4| 26.3 
Salinity, o/oo 33-9 (34.0 )34.0|Hydrogen ion pH $212)8.12/8.09 
Volume of tow, ecm® HUGS) 36 96} Length of tow,miles is 1.3) 1.3 
\Acrocalanus gibber 1 
gracilis | 
Clausocalanus arcuicornis | 
| furcatus | | 
lCorycaeus crassiusculus | 
pumilus | 
| typicus 
‘Eucalanus elongatus 
‘Euchaeta acuta 
‘Euchirella rostrata 
\Parranula curta 
‘Lucicuta clausi 
Mecynocera clausi 
Megacalanus longicornis 
Microcalanus pusillus 
3 |Neocalanus gracilis 
robustior 
tenuicornis 
}Oithona brevicornis 
i 
f 
similis 
spinirostris 
‘Oitnonina nana 
‘Oncaea conifera 
| media 
minuta 
Similis 
| venusta 
Paracalanus parvus 
‘Pleuromamma gracilis 
|Pseudocalanus minutus 
bs pygmaeus \Sapphirina angusta 
Canthocalanus: pauper : ‘Scolecithrix danae 
Farranula rostrata | | Undinula darwini 
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Was 
REMARKS. From a low surface temperature there t#® a drop of four and a nalfr 
degrees in the uvper 100 metersywhile the salinity and hydrogen ion remained 
moderately high and constant. Four: species only Soveen at the surface,, 
twenty-four: in the 50+meter tow and twenty-five in the 100-meter tows 
Twenty-one species: (60%) were each confined to a single tow and only two 
Species: were found in all three tows To account for the very small num- 
ber of species found at the surface it is shown elsewhere that the combina- 
tion of a rather low temperature and a moderate salinity is not favorable to 
the copenods.. 
But a better reason is found in the fact that the great bulk of this 
tow. was; made up of Ctenopnores« These feed upon covevods amongst othe 
Creatures and when they swarm in large numbers,as they were doing here,thney 
Would naturally reduce the number of the copevodss This would also help 
to explain the great drop in the number or Species from 108 at Station 56 and 
60 at Station 57 down to tne 36 species here. 

