COPEPODA FROM IFALUK ATOLL 115 



leg 2 

 legs 

 leg 4 



Top of exopodite of leg 5 reaches middle of genital somite; apex 

 of baso-endopodite reaches middle of exopodite. 2 setae at baso- 

 endopodite and 1 fine seta on haired external lobe. Total number 

 of setae on exopodite 6, external margin haired. 3 of these setae 

 at apex and 3 along external margin. Shape of exopodite elongated 

 ovate, 2]i times as long as wide (fig. 376.) 



The specimen (as all other specimens) is practically colorless, very 

 faintly yellowish, no eye or eyespot visible. One of the females 

 from locality 589 is ovigerous, carrying a sac with 10 eggs. 



Adult male, total length 0.36 mm.; greatest diameter 0.14 mm.; 

 length of longest furcal seta 0.15 mm. 



General shape of body, especially cephalothorax, strongly suggestive 

 of that of female, compressed dorsoventrally, ovoid in outline, with 

 distinct division between cephalothorax and abdomen, with propor- 

 tional length of 18:8 (fig. 37c). Rostrum invisible from above; in 

 lateral aspect, forms conical eminence, almost hidden between basal 

 parts of antennules, and points downward. Line of back, in lateral 

 view, very straight, at anterior end of cephalon curving strongly 

 into rostrum (fig. 386). Length of cephalic somite slightly superior 

 to combined lengths of thoracic somites 2 to 4. Epimeral plates of 

 2nd thoracic somite produced into bluntly pointed parts; on thoracic 

 somites 3 and 4 these plates are rounded. 



5th thoracic somite small, pointed in dorsal aspect. Genital (1st 

 abdominal) somite fairly long, IK times length of 2nd abdominal 

 somite; all abdominal somites have smooth margins. Anal somite 

 very short, anal flap invisible. Rami of furca about as long as ^vide, 

 with 5 marginal setae and 1 appendicular seta. Setae 1 and 4 of nearly 

 same length, short. Setae 2 and 3 lengthened and thickened, es- 

 pecially 2nd; seta 5 placed halfway along external furcal margin, 

 small. 



Antennules (fig. 39j) composed of 9 segments, 4th and 5th seg- 

 ments completely fused to form large, slightly swollen segment with 

 conical process, carrying aesthetasc and 2 setae. Between segments 

 7 and 8 the articulation is indistinct; two of the apical setae of 

 segment 9 may have sensory function and have thickened bases. 



Antenna (fig. 39e) with basis and 1st endopodal segment separate. 

 Exopodite 4-segmented, number of setae 2, 1, 1, and 3, respectively. 

 Endopodal segment 1 with seta halfway along internal margin; 2nd 

 segment with 2 internal and 6 apical setae, 4 of which are geniculate. 



