ABSTRACT 



A systematic study was made of the calanoid copepods found in 14 zooplank- 

 ton samples, four of which were obtained from within the recently discovered 

 equatorial undercurrent (Cromwell current), collected between 5° N. and 5° S. 

 and 130° E. and 120° W. 



One hundred and ten species belonging to 18 families were recorded. 

 Descriptive notes, measurements and figures were given for most species with 

 citations to previous occurrences in the Pacific Ocean. 



Except for Scolecithricella tenuiserrata (Giesbrecht), the copepod species in 

 samples collected from within the equatorial undercurrent were not very differ- 

 ent from those in samples obtained adjacent to the current. The numerical 

 abundance and species diversity in equatorial waters were briefly compared 

 with that reported for the northwestern Pacific Ocean. Acrocalamis ander- 

 soni Bowman, Chirundina indica Sewell and Haloptilus fertilis (Giesbrecht) 

 were reported for the first time from the Pacific Ocean. 



Three species, Xanthocalmius dilatiis, Aviallophora sviithae and Scolecithri- 

 cella tropica, are described as new, and hitherto unknown males of Gaetamis 

 miles Giesbrecht and G. minor Farran are briefly illustrated from juvenile spe- 

 cimens. It was proposed that Euchirella brevis Sars is a synonym for E. 

 amoena Giesbrecht; Eucluieta consimilis Farran for E. concinna Dana; Scoeci- 

 thrix longicornis Scott, and Scolecithricella spinipedata Mori for Scolecithricella 

 ctenopus (Giesbrecht) ; and Centropages pacificus Chiba for C. elongatus Gies- 

 brecht. 



IV 



