COPEPODA FROM IFALUK ATOLL 349 



Antenimles (fig. 138/) short, slightly shorter than cephalic somite, 

 6-segmented. 1st segment with 2 teeth, placed in different planes, 

 with the result that only one is visible in dorsal aspect. Segment 4 

 with small conical process, bearing aesthetasc and 2 setae. 



Since the antenna and mouth parts are identical with those of the 

 male, of which I obtained a better dissection, those of the female will 

 be described with the male. 



Leg 1 (fig. 138a) with big basis, carrying fine external seta and 

 spinulose internal tubercle. Exopodite 2-segmented, without in- 

 ternal setae. 2nd exopodal segment with 5 appendages; 2 geniculate 

 apical setae very long. 1st endopodal segment styliform, 4 times as 

 long as exopodite, 6 times as long as wide; internal border with num- 

 ber of very strong hairs. 2nd and 3rd endopodal segments fused, 

 with small seta near line of fusion, forming pointed, curved digit. 



Legs 2 to 4 wdth 3-segmented exopodites and 2-segmented endop- 

 odites; 1st endopodal segment of these legs without setae. The 

 details of these legs appear from figures lS8b-d and the setal formula: 



endopodite exopodite 



leg 2 0.221 0.1.123 



leg 3 0.321 0.1.223 



leg 4 0.221 0.1.223 



Leg 5 big, baso-endopodite and exopodite lengthened, reaching end 

 of 2nd abdominal somite. Baso-endopodite reaching K length of 

 exopodite, with total of 4 setae, median seta placed almost at proximal 

 end of internal margin. Exopodite 4 times as long as wide, with 

 total of 6 setae. Shape and arrangement of setae can best be judged 

 from figure 138e. External lobe big, with strong seta. Whole 5th leg 

 densely haired. 



Color strongly faded, opaque greenish, cup-shaped depressions of 

 cephalic somite transparently greenish. 



Adult male, total length 0.41 mm.; greatest diameter 0.12 mm.; 

 length of longest furcal seta 0.37 mm. 



Body slenderer than in female, with cephalothorax and abdomen 

 well separated. Various somites of body stand out very clearly 

 because of shallow ring-shaped constrictions at beginning of each 

 somite (fig. 141c). Head and 1st thoracic somite fused, rostrum 

 smaller than in female, rounded anteriorly, reaching half length of 

 1st antennular segment. Cephalic somite longer than combined 

 lengths of thoracic somites 2 to 4, laterally scarcely produced, with 

 the result that conical oral field is free for observation (fig. 132a). 

 Thoracic somites 2 to 4 of equal length, epimeral plates rounded, nude. 



5th thoracic somite short, visible dorsally and laterally. Abdominal 

 somites 1 to 4 of equal length, 1st and 2nd completely free. None of 

 abdominal somites with laterally produced epimeral plates. Anal 



