188 U.S. NATIONAL MUSEUM BULLETIN 23 6 



Antennules (fig. 69/) subchirocerate, 9-segmented; segment 3 small, 

 segments 4 and 5 almost fused to form swollen base of hinge, with 

 small process bearing aesthetasc and 2 setae. Ultimate segment very 

 small. 



Antenna with normally developed setae on endopodite, allobasis, 

 and 2-segmented exopodite. 



Leg 1 (fig. 69a) with strongly developed spines on basis, internal 

 spine cm-ved inward, external spine straight. Endopodite 2-seg- 

 mented, 1st segment styliform, seta at internal margin inserting at 

 upper third. Exopodite 3-segmented, segments of nearly equal 

 length; appendages of exopodite normally developed, external margin 

 strongly spinulose. 



Legs 2 to 4 (figs. Q9b-d) with the following setal formula: 



endopodite exopodite 



leg 2 1.221 (modified) 1.1.123 



leg 3 1.1.021 (modified) 0.1.223 



leg 4 1.1.121 0.1.2(3)23 



Endopodite of leg 2 modified, 1st segment normally developed, 2nd 

 segment lengthened, reaching apex of exopodite. There are 2 internal, 

 2 apical, and 1 external (subapical) setae (fig. 696). 



Endopodite of leg 3 also modified. 1st segment normally developed, 

 with short internal seta. Segment 2 with external conical process, 

 forming part of hollowed cylinder, fitting around basal part of segment 

 3; 1 internal seta. 3rd segment with external apical process, which 

 may represent seta fused to segment, and 2 apical setae (fig. 69c). 



Leg 4 normally developed; apex of endopodite reaching halfway 

 along 3rd exopodal segment. There is an exceedingly fine third 

 internal seta on that segment of the exopodite (fig. Q9d). 



Exopodite of leg 5, 2-seg-mented; apex of baso-endopodite reaching 

 the articulation, with 2 apical setae. 1st exopodal segment with 

 external spine; 2nd segment with 2 apical spines, 2 apical setae, and 

 2 internal marginal setae (fig. 69e). 



Color completely faded, no eye or pigmented spot visible. 



Remarks. — The two specimens from locahty 590 described above 

 approach Parastenhelia hornelli Thompson and A. Scott, 1903, in the 

 structure of the exopodite of leg 1, where the 3 segments have about 

 the same length. This species, which has never again been recorded 

 after the original record from the pearl oyster banks around Ceylon, 

 is much larger (9 about 1 mm., cf 0.8 mm.) and has a different 

 setation of the legs (as far as these have been described). Since the 

 specimens found in the Ifaluk collection have the setal formula char- 

 acteristic for P. sjrinosa and since some variability in the structure 

 of leg 1 in this very variable species seems very likely, I have recorded 

 the specimens as P. spinosa. P. ornatissima (Monard, 1935a), a 



