COPEPODS FROM EQUATORIAL WATERS OF PACIFIC OCEAN 



215 



Remarks: The small size and large ventral 

 protrusion on the genital segment (figs. 3, 4) 

 will identify the female. The geniculate right 



antenna and the pointed terminal segment of 

 this antenna (figs. 10, 11) will aid in recogniz- 

 ing the male sex. 



Family METRIDIIDAE 



Metridia icniista Giesbrecht, 1889 

 (Plate 20, figs. 13-17) 

 Pacific records: Vervoort, 1957. 



Vessel: Station Occurrence 



Hugh M. Smith 144 1 juvenile female, 



2.88 mm.; 1 male, 

 2.82 mm. 



Remarks : This species is recognized by the 

 asymmetrical furca. In both sexes the left 

 furca is longer than the right one (figs. 13, 16). 



PleHiomamma xipbias (Giesbrecht, 1888) 



(Plate 20, figs. 18-21, plate 21, figs. 1-5) 



Pacific records: Vervoort, 1957. Also, Johnson, 

 1942; Mori, 1942; Brodsky, 1950; Anraku, 19.52; Honjo, 

 1952; Anraku, 19.54b; Tsuruta and Chiba, 1954a; 

 1954b; Chiba, Tsuruta, and Maeda, 1955; Hida and 

 King, 1955; Nagaya et al., 1955; Chiba, 1956; Hein- 

 rich, 1957b; Honjo et al., 1957; Heinrich, 1958b; 

 Yamazi, 1958a. 



Vessel: Station 

 Hugh M. Smith __ 63 _. 

 Orsom 10 _. 



Occurrence 



1 male, 4.28 mm. 



2 females, 3.99, 4.08 



mm.; 2 males, 

 3.99, 4.08 mm. 



Satsuma 32 1 female, 4.25 mm.; 



1 male, 4.18 mm. 



Remarks: The large spine-like protrusion 

 on the forehead of this species (figs. 19, 3) 

 readily distinguishes it from other species in 

 the genus. 



Pleiiromamma ahdominalis (Lubbock, 1856) 



(Plate 21, figs. 6-15) 



Pacific records: Vervoort, 1957. Also, Johnson, 

 1942; Mori, 1942; Brodsky, 1950; Anraku, 1952; Honjo, 

 1952; Anraku, 1954a; 19.54b; Tsuruta and Chiba, 

 1954b; Chiba, Tsuruta, and Maeda, 1955; Hida and 

 King, 1955; Nagaya et al., 1955; Chiba, 1956; Hein- 

 rich, 1957b; Honjo et al., 1957; Heinrich, 1958a; 

 Yamazi, 1958a. 



Vessel : 



Station 



Hugh M. Smith 94 



Do 29 



Do 63 



Orsoyn 10 



Horizon 32 3.06(1) 



Satsuma 32 2.8.5-3.13(5) 2.99-3.06(4) 



Occurrence (measurements in mm.; number of specimens in paren.) 

 f. typica f. edentata f. abyssalis 



female male female male 



3.02(2) 



3.13(1) 2.7.5-3.06(11) 3.06(1) 



2.75-2.82(2) 



2.79-3.02(3) 



Remarks : All three forms of this species ap- 

 peared in the above cited samples. Figures 

 and descriptions of these have been presented 

 by Steuer (1932). The female of forma abys- 

 salis is not known. The female of forma typica 

 and forma edentata are distinguished by the 

 teeth on the first and second antennal seg- 

 ments. In forma typica these segments each 

 has a large tooth (fig. 6) while in foi-ma eden- 

 tata these segments have only small teeth (fig. 

 10). Although Steuer mentions that segment 



16 of the first antenna is smaller than segment 



17 in forma edentata, these length differences 

 are difficult to observe. 



The male of forma edentata is unknown. 



Forma typica is easily recognized by the greatly 

 asymmetrical and hairy abdomen (fig. 7) while 

 the male of forma abyssalis has a less asym- 

 metrical and less hairy abdomen (fig. 12). The 

 small tooth on segment 17 (fig. 13) makes this 

 specimen referable to what Steuer termed sub- 

 form thermophila of forma abyssalis. 



Phinnm.im)iia indica Wolfenden, 1905 



(Plate 22, figs. 1-7) 



Pacific records: Tanaka, 1953. 



Vessel : Station Occurrence 



Satsuma 32 1 male, 2.04 mm. 



