LISTS OF SPECIES BY STATIONS 



107 



X'olume of tow, 48 cm'; length, 0.1 mile; time, 7'' 50"" to 

 lO*" P.M.; surface only. This nocturnal tow yielded 46 species, 

 about as many as were obtained in both tows at each of 

 stations 89 and 90. Nineteen species which were confined to 

 the 50-nieter tow- at stations 89 and 90, one or both, were 



here found at the surface. In addition, 13 species were here 

 present at the surface at night which did not appear in the 

 daytime tows at stations 89 and 90. Thirty of the species, 

 therefore, give good evidence of nocturnal migration. Cory- 

 c.aetis, Farranula, and Oncaea were especially abundant. 



Station 90 

 March 25, 1929; 16° 35' S, 155° 45' W; bottom depth, 4630 m; 45 species 



Depth of tow, m 

 Temperature, °C 



Salinity, 0/00 

 X'olume of tow, cm' 



Acartia danae 



Acrocalanus gracilis < f 



monachus f 



Calanus minor 



propinquus 



Candacia bispinosa 



simplex 



Centropages calaninus 



Clausocalanus arcuicornis 1 



Copilia denticulata f 



quadrata 1 



vitrea 



Corycaeus anglicus 1 



catus 2 



crassiusculus c 



longistylis f 



speciosus c 



typicus 3 



Euchaeta acuta 



marina c 



Farranula carinata c 



curta r 



gibbula r 



Farranula rostrata f c 



Labidocera detruncata f 



Macrosetella gracilis . . 1 



Mecynocera clausi 2 



Microcalanus pygmaeus . . a 



Microsetella norvegica . . 2 



rosea . . f 



Oithona attenuata . . f 



plumifera . . f 



similis f 



spinirostris . . 2 



Oncaea media . . f 



minuta f c 



similis r 



venusta f f 



Paracalanus parvus f c 



Pontella tenuiremis 



Pontellina plumata 



Pseudocalanus minutus . . c 



Sapphirina nigromaculata . . 1 



Scolecithrix danae . . a 



Spinocalanus magnus . . 1 



The temperature, salinity, and hydrogen-ion concentration 

 varied extremely little at the two depths. Twenty-five species 

 were present at the surface and 34 in the 50-meter tow. 

 Thirty-one species (70 per cent) were found in one tow but 

 not in the other, and 14 were common to both tows. Cory- 

 caeus. Farranula. and Oncaea were well distributed between 



the two tows, but Oithona was much more abundant in the 

 deeper tow. The 50-meter tow was two and a half times as 

 large as the surface tow although its length was only one- 

 half greater. Paracalanus appeared in both tows, but Pseudo- 

 calanus was confined to the deeper tow, along with Calanus 

 and Candacia. 



