COPEPODA FROM IFALUK ATOLL 57 



small, with single seta. Segments 1 and 2 of endopodite wealdy sepa- 

 rated, with number of longitudinal ridges of small scales or spinules; 

 those along frontal border better developed, pectiniform. Near the 

 end of the 1st endopodal segment a strong curved seta and a short 

 process with a pectiniform row of hairs insert; near the (indistinct) 

 articulation with the 2nd segment there are 3 more hooked spines and 

 a seta. Labrum a broad, bilobated structure in front of the mouth 

 parts, densely covered with short hairs (fig. 16e). 



Mandible (fig. 15/) with distinct, well-developed, internally directed 

 praecoxal process, forming sharp manducatory plate, edge of which 

 indistinctly denticulate. This manducatory plate has either a short 

 seta or a small tooth, closely pressed against the plate. I failed to 

 observe a palp. Immediately caudally of the manducatory processes 

 there is a pair of haired paragnaths, at the base of which, wedged 

 between the basal portions of mandible and maxilla, is a small, 

 rounded structure, the maxillule, fused to the oral field and bearing 3 

 short setae (fig. 16e). Maxilla medially produced into 2 haired proc- 

 esses, representing teeth or setae supported by one of endites (fig. 16/). 

 In addition, there appears to be a fine seta at the base of the teeth. 

 The labium was damaged during dissection, with the result that I 

 could not observe the structure. 



Maxillipedes particularly big and very prominent structures of 

 ventral aspect of cephalic somite (fig. 16g). Coxa small, attached 

 close to median line, turned outside, strongly attached to ventral waU 

 of cephalic somite. Basis large, elongated triangular, length axis in 

 longitudinal direction, with the result that articulation between basis 

 and endopodite lies near point of attachment of antennae and is hidden 

 under curved edge of cephalic somite. Endopodite strongly reduced 

 to form highly chitinized, sigmoid claw with external auxiliary tooth. 

 There is a fine seta on the claw near its insertion and a plumose seta 

 on the basis just visible in the curve of the claw. 



Leg 1 (fig. 16a) strongly flattened, coxa and basis fused, without 

 marginal spines or setae. Exopodite indistinctly 3-segmented, endop- 

 odite distinctly 3-segmented. Apical exopodal segment with 6, big, 

 densely plumose, marginal setae and 2 external marginal spines; 

 exopodal segments 1 and 2 each have 1 external marginal spine. 

 Endopodal segments 1 and 2 each with strong internal seta; there 

 are no external setae on these segments. The 3rd endopodal segment 

 has a total of 5 plumose setae. 



Legs 2 to 4 (figs. IQb-d) with transversally elongated and directed 

 coxae and short bases. Coxae strongly swoUen; bases also swollen, 

 wdth single seta placed on caudal surface of segment near insertion 

 of exopodite; in my dissections this seta is usually curved between 

 endopodites and exopodites. Endopodites and exopodites 3-seg- 



