LISTS OF SPECIES BY STATIONS 



Depth of tow, m 

 Temperature, °C 

 Salinity, o/oo 

 Volume of tow, cm^ 



Station 50 

 November 29, 1928; 26° 27' S, 115° 21' W; bottom depth, 2837 m; 66 species 



50 100 Depth of tow, m 



23.2 22.0 20.5 Density (<rtp) 



36.0 35.9 35.7 Hydrogen-ion cone. (pH) 



32 32 i2 I^ength of tow, miles 



Acartia negligens . . 1 



Acrocalanus gracilis . . r 



Aetideus armatus 



Calanus tonsus 



Calocalanus pavo . . 1 



st\Iiremis 



Candacia simplex 



Centropages calaninus r 1 



Clausocalanus arcuicornis . . r 



Clytemnestra scutellata . . 1 



Copilia denticulata 1 



quadrata 



Corycaeus agilis 



catus 



crassiusculus . . 2 



flaccus 4 



lautus 3 f 



limbatus 



longistylis 



speciosus 2 



typicus . . r 



Euchaeta acuta 



marina . . 3 



Euchirella brevis 



Farranula carinata 



concinna r 



gibbula a a 



gracilis c c 



rostrata c a 



Haloptilus longicornis 



spiniceps 



Heterorhabdus spinifrons . . 3 



Lucicutia clausii 



Icf 



Lucicutia flavicornis. . . . 

 Macrosetella gracilis. . . . 



Mecynocera clausi 



Metridia brevicauda. . . . 

 Microcalanus pusillus. . . 



pygmaeus 



Microsetella rosea 



Neocalanus gracilis 



robustior 



Oithona attenuata 



bre\"icornis 



similis 



spinirostris 



Oncaea media 



minuta 



similis 



subtilis 



tenella 



venusta 



Paracalanus parvus 



Pleuromamma gracilis. . 

 Pontella atlantica 



princeps 



tenuiremis 



Pontellina plumata 



Pseudocalanus minutus. 

 Sapphirina auronitens. . 



nigromaculata 



Scolecithricella minor. . . 

 Spinocalanus abyssalis. . 



caudatus 



Undinula darwinii 



V'aldiviella minor 



f 



1 



1 



Id' 



1 



19 



c 



19 



Seventeen species were found at the surface, 34 at the 50- 

 meter level, and 42 at the 100-meter level. Fort>--five species, 

 or about two-thirds, were each confined to a single tow, and 

 only 5 were present in all three tows. There was less than 3° 

 difference in the temperature at the three depths, and prac- 

 tically no difTerence in the salinity and h>drogen-ion concen- 

 tration. The smaller species of Corycaeus, Farranula, and 



Oncaea are much in evidence at this station. But again, 

 whereas Corycaeus and Farranula species appear in all three 

 tows, the Oncaea species are entirely absent from the surface. 

 The 100-meter tow contains one of two records of Valdiviella 

 minor outside the 1000-meter tow at station 64 (6). The two 

 Haloptilus species are in the 100-meter tow, but Heterorhabdus 

 appears in the 50-meter tow. 



