70 



COPEPODS OF LAST CRUISE OF CARNEGIE 



The temperature at the surface was moderate, and dropped 

 2° at 50 meters and 2° more at 100 meters; the salinity and 

 hydrogen-ion concentration showed but httle change. Twenty- 

 seven species were taken at the surface, 63 in the 50-meter 

 tow, and 92 in the 100-meter tow. This last is the largest num- 

 ber of species taken in a single tow during the entire cruise. 

 Forty-nine species (45 per cent) were each confined to a single 

 depth and 15 were present at all three depths. 



The 14 species of Corycaeus and the 10 species of Oncaea 

 make the banner record for these two genera at any single 

 station, and it is worth noting that these 24 species, together 

 with the 5 species of Oithona, are distinctly congregated in 

 the two deeper tows. Aetidetis, Candacia, Euaetideus, Halop- 

 tilus, Heterorhabdus, and Megacalanus were also confined to 



the two deeper tows; the same species of Sapphirina that 

 appeared only in the 100-meter tow at station 55 were here 

 distributed in all three tows. Although the surface tow yielded 

 27 species, the 2 species of Clausocalanus, 1 species of Para- 

 calanus. and 1 of Pseudocalanus constituted together fully 

 90 per cent of the copepods, with the other species little more 

 than stragglers. The 100-meter tow contains the only record 

 of Scaphocalanus mediics for the entire cruise, represented by 

 a single specimen. The 2 species of Acartia and the 3 of 

 Calocalanus did not show a single specimen in the surface 

 tow, but the 5 species of Farranula were quite e\'enl\' dis- 

 tributed in all three tows. One species of Macrosetella was 

 confined to the surface, the other appeared only in the 100- 

 meter tow. 



Between st.\tions 56 .\nd 57 

 December 19, 1928; 32° 27' S, 107° 22' W; 18 species 



Acrocalanus gracilis a 



Candacia bispinosa 1 



Centropages calaninus f 



Clausocalanus arcuicornis a 



furcatus a 



Corycaeus agilis 1 



Corycaeus pumilus f 



Farranula gibbula 4 



rostrata f 



Labidocera detruncata 1 



Macrosetella gracilis r 



Oncaea minuta c 



Oncaea notopa f 



venusta f 



Pontella tenuiremia 1 



Pseudocalanus minutus r 



Sapphirina auronitens 2 



opalina 2 



Volume of tow. 36 cm'; length, 1.3 miles; surface only. This 

 tow is made up very largely (98 per cent) of Acrocalanus and 

 Clausocalanus and contains no species that was not found at 



regular station 56 or 57 except Labidocera detruncata. The 

 time of the tow was not recorded, but it was probably a noc- 

 turnal one between stations while the vessel was becalmed. 



