ern end of the area were Cdlanus glacialis, C. 

 pacificiis, C. phonchrus, Eucalanus Intngii, 

 Ctenocalaiuis vanus, Heterorhabdus papiUiger, 

 and Cojidacia bipinnata. The common species 

 toward the southern end of the area were Cal- 

 avus te)U(icoyuis, NcnnwcalcDius minor, Neocal- 

 anus gracilis, N. robitstior, Eucalanvs elori- 

 gatus, Euchaeta spi)iosa, Centropages eloiigatits, 

 Haloptilus loiigicornis, Candacia ethiopica, 

 Paracandacia bispinosa, and Acartia negligens. 

 EiichireUa rostrata was fairly common in the 

 area except at the extreme ends. Euchaeta 

 media was common at one station and Centro- 

 pages bradiii at two. 



The calculated number of copepods per cubic 

 meter of water varied from 1.1 at station 7 to 

 110.6 at the northernmost station (table 2). In 

 comparison, Grice (1962) obtained 2.3 to 3.7 

 calanoids per cubic meter of water for tows at 

 the surface and at to 100 m. in the equatorial 

 Pacific; however, he calculated a mean number 

 of 26.8 copepods per cubic meter of water for 

 depths between about 50 and 150 m. Brodsky 

 (1952) reported a far greater abundance of 

 copepods in the northwestern Pacific — 5,040 

 per cubic meter of water for the 50- to 100-m. 

 level, and 320 for the 100- to 200-m. level. 



Of all the previous studies only Brady (1883) 

 and Wilson (1942) reported planktonic cope- 

 pods from the area under consideration. Brady 

 listed the following nine species of calanoid 

 copepods obtained in a surface plankton sample 

 collected on July 21, 1875, from Challenger sta- 

 tion 256 (lat. 30°22' N., long. 154°56' W.), 

 which corresponds closely to station 3 of the 

 present collections : 



Uyidimda vulgaris 

 U. darivini 

 Evchaeta marina. 

 Plevromamma abdominalis 

 Centropages violacens 

 Candacia tnnicata 

 Labidocera aciitifrons 

 L. detriiiicata 

 Pontellopsis villosa 



Of these only Euchaeta marina and Centro- 

 pages violaceus were in the present collections. 

 Of the remaining species, five were reported 

 from the area by \Mlson (1942), and two. 



Pleuromamma abdominalis and Candacia tru)i- 

 cata, were obtained from equatorial waters by 

 Grice (1962). 



Wilson (1942) reported 48 species of cala- 

 noid copepods in plankton samples collected in 

 early October in to 100-m. tows at Carnegie 

 stations 141-145 (between lat. 29°02' N. and 

 lat. 34°06' N., and between long. 145'30' W. 

 and long. 160°44' W.). These stations are in 

 about the same area as the three southern sta- 

 tions of the present collections. Of the 48 spe- 

 cies the following 26 were not in the present 

 collections : 



Megacalan us longicornis 



* Can thocalanus pauper 



* Undimda vidgaris 

 *U. darwini 

 *Paracalamts aculeatus 



P. pygmaeus 



Acrocalanus gibber 



A. gracilis 

 *A. longicornis 



Calocalan us stijliremis 



Microcalan us pusillns 



M. pygmaeus 

 *Clausocalanus furcatus 

 *Enchirella curticauda 

 *E. pulchra 



Euchaeta acuta 



E. tonsa 

 ^Centropages calani)) us 



Lucicutia claiisii 



* Haloptilus acntifrons 

 *Candacia simplex 

 *Pontella tenuiremis 



Po7itellopsis I'iUosa 



* Labidocera detruncata 

 L. acutifrons 



L. nerii 



Most of these species are tropical or sub- 

 tropical; 13 species (marked with an asterisk) 

 were found by Grice (1962) in equatorial 

 waters of the Pacific Ocean. If the difference in 

 dates of collection is considered, seasonal 

 changes may account for the absence of many 

 tropical or subtropical copepods in the present 

 collections that were reported in the two pre- 

 vious studies. 



CALANOID COPEPODS FROM NORTH PACIFIC 



529 



