LISTS OF SPECIES BY STATIONS 



71 



Station 57 

 December 20, 1928; 33° 59' S, 106° 43' W; bottom depth, 3139 m; 80 species 



Depth of tow, m 

 Temperature, °C 

 SaHnity, 0/00 

 \olume of tow, cm' 



50 100 Depth of tow, m 50 100 



18.9 15.5 14.3 Density (<rtp) 24.6 25.5 26.1 



34.4 34.3 34.3 Hydrogen-ion cone. (pHj 8.14 8.14 8.12 



48 32 48 Length of tow, miles 1.2 1.2 1.2 



Acartia danae 



negligens 



Acrocalanus gibber 



graciUs 



Calanus minor 



Calocalanus pavo 



plumulosus 



Candacia bispinosa 



simplex 



Centropages calaninus. . . . 

 Clausocalanus arcuicornis. 



furcatus 



Clytemnestra rostrata. . . . 

 Copilia denticulata 



quadrata 



Corycaeus catus 



clausi 



crassiusculus 



flaccus 



furcifer 



lautus 



limbatus 



longistylis 



pumilus 



typicus 



Eucalanus crassus 



elongatus 



mucronatus 



Euchaeta acuta 



Euchirella brevis 



Farranula carinata 



curta 



gibbula 



gracilis 



rostrata 



Haloptilus longicornis 



plumosus 



1-ubbockia aculeata 



Lucicutia clausii 



flavicornis 



Macrosetella oculata 



Mecynocera clausi 



Megacalanus longicornis. 

 Microcalanus pusillus. . . . 



pygmaeus 



Microsetella rosea 



Miracia eflferata 



Neocalanus gracilis 



robustior 



tenuicornis 



Oithona attenuata 



brevicornis 



plumifera 



similis 



spinirostris 



Oithonina nana 



Oncaea media 



mediterranea 



minuta 



notopa 



similis 



tenella 



venusta 



Paracalanus aculeatus. . . 



parvus 



pygmaeus 



Phaenna spinifera 



Pleuromamma gracilis. . . 

 Pontella danae 



tenuiremis 



Pontellina plumata 



Pseudocalanus minutus. . 

 Sapphirina angusta 



auronitens 



nigromaculata 



Scolecithricella bradyi . . . 



Scolecithri.\ danae 



Spinocalanus abyssalis. . . 

 Undinula caroli 



darwinii 



The moderate surface temperature dropped 3° at 50 meters 

 and another degree at 100 meters; the salinity and hydrogen- 

 ion concentration were fairly high and remained constant. 

 Only 4 species appeared in the surface tow, 48 in the 50-meter 

 tow, and 66 in the 100-meter tow. Forty-four species (55 per 

 cent) were each confined to a single tow and only 2 were 

 found in all three tows. Although the two genera Corycaeus 

 and Oncaea do not come up to their record at station 56, they 

 are still well represented in species — 10 for the former and 7 

 for the latter. Of the 1 7 species, 2 species of Corycaeus are the 



only ones that appear at the surface, the other 15 being con- 

 fined to the two deeper tows. Although every one of the 5 

 species of Farranula appeared at the surface in goodl>- num- 

 bers at station 56, not one of the same 5 species was found 

 here in the surface tow. This would seem to indicate that 

 Farranula may become somewhat phototropic, although 

 usually much less so than Corycaeus and Oncaea. AH the 

 specimens in the surface tow were very badh' mutilated, and 

 if this means an accident, it will go far toward explaining the 

 exceptionally small number of species in that tow. 



