COPEPODS FROM EQUATORIAL WATERS OF PACIFIC OCEAX 



175 



samples collected from adjacent waters — north 

 {Smith 132), south {Smith 153), and above 

 {Smith 30) and below {Smith 29) the under- 

 current — was not particularly distinctive. Sco- 

 lecithricella tenuiscnata, although apparently 

 absent from one undercurrent sample {Smith 

 94), did appear in the other three samples and 

 also in two other samples {Sntith 63, Stranger 

 34) that were collected from depths where the 

 undercurrent could be located, if present, but 

 several hundi'ed miles west of its known limits. 

 Knauss (1959), has indicated that the current 

 may extend as far west as about 160° E. ; in 

 that event the above two samples could have 

 been collected from the current. Even if S. 

 tenuiserrata is typically found within the un- 

 dercurrent, it cannot be considered as an "indi- 

 cator" sensu stricto of the current. In addi- 

 tion to the present samples, this species has 

 been reported from near the Great Barrier 

 Reef (Farran, 1936) and from Japan (Tanaka, 

 1953). 



Numerical abundance 



The number of copepods calculated for those 

 collections in which a current meter was em- 

 ployed, varied from 2.3 to 56.4 with a mean of 

 21.8 copepods per cubic meter (table 2). These 

 data may be compared to numerical data pre- 

 sented by Brodsky (1952) for the northwestern 

 Pacific Ocean. Using only those collections in 

 which closing nets were used {Smith 94, 132, 

 144, 153, 178, and 31), a mean number of 26.8 

 copepods per cubic meter was calculated for 

 depths between approximately 50 and 150 

 meters in the eastern Pacific Ocean. Brodsky's 

 data included numerical abundances for seven 



different vertical levels. For the 50 to 100-m. 

 level he gave a figure of 5,040 calanoids per 

 cubic meter and for the 100 to 200-m. level, 

 320 per cubic meter. Nine species were pres- 

 ent at the former level and ten at the latter 

 level. In comparison, there were no less than 

 25 species in any of the aforementioned eastern 

 Pacific closing net samples. 



TAXONOMY 



For each species I have given references to 

 its occun-ence in the Pacific Ocean, with the 

 exception of those early records summarized by 

 Giesbrecht and Schmeil (1898) and those cited 

 by Vervoort (1946, 1957). The former refer- 

 ence has usually been omitted in the following 

 sections. I have given measurements for sev- 

 eral individuals of a species and usually at all 

 stations where it occurred. The total-length 

 measurements are from the tip of the forehead 

 to the end of the furca, without regard to the 

 telescoped portions of the abdominal segments, 

 and are recorded in mm. unless otherwise indi- 

 cated. Except for PseudochireUa. copepodids 

 which could not be assigned to a species are 

 not mentioned. 



Included under Remarks are certain taxo- 

 nomic or ecological notes and usually a few 

 brief statements on the diagnostic characters 

 of the species. It is hoped that the specific 

 characters mentioned and the figures presented 

 for each species will be useful to others making 

 identifications of tropical calanoid copepods. 

 All illustrations were made with a camera lu- 

 cida. 



Family CALANIDAE 



Calanns tenuicornis Dana, 1849 



Pacific records: Vervoort, 1946. Also, Yamada, 

 1933; Johnson, 1942; Mori, 1942; Davis, 1949; Brodsl<y, 

 1950; Motoda, Iizul<a, and Anraku, 1950; Motoda and 

 .\nial<u, 1951; Anraku, 1952; Honjo, 1952; Motoda and 

 Anraku, 19.52b; Nakai, 1952; Anraku, 1953; Tanaka, 

 1953; Yamazi, 1953a; 1953c; Anraku, 1954a; 1954b; 

 Motoda and Anraku, 1954; Tsuruta and Chiba, 1954a; 

 1954b; Yamazi, 1954b; 1954d; Bowman, 1955; Chiba, 

 Tsuruta, and Maeda, 1955; Motoda and Anraku, 1955; 

 Nagaya et al., 1955; Yamazi, 1955a; Chiba, 1956; 



Tanaka, 1956a; Heinrich, 1957a; Honjo et al., 1957; 

 Heinrich, 1958b; Yamazi, 1958a; 1958b; Brodsky, 1959; 

 Lindberg, 1959; Ponomareva, 1959. 



Vessel: Station Occurrence 



Hugh M. Smith __ 94 1 female, 1.87 mm.; 



1 male, 1.80 mm. 



Do 132 present. 



Do 153 1 female, 1.75 mm.; 



1 male, 1.56 mm. 



Do 178 present. 



Horizon 32 1 female, 1.68 mm. 



