160 PROCEEDINGS OF THE NATIONAL MUSEUM vol. los 



Male 



Length, 0.63-0.68 mm. Forepart of body strongly curved (fig. 32). 

 Urosome 5-segmented, the fifth segment reduced. Antennules reach- 

 ing beyond the metasorae; the left like that of the female, the right 

 (fig. 29) with 24 free segments, four beyond the point of geniculation. 

 (See pp. 163-167 for comparison of segmentation with gracilis.) 

 Segments 13 and 14 modified as in gracilis but completely separated 

 (fig. 30). Segment preceding the geniculation without a combhke 

 group of spinules. 



Cephalic appendages and legs 1-4 as in female. 



Leg 5 (figs. 33-35) : First basal segments reduced in size and com- 

 pletely fused. Second basal segments of nearly equal size. Right exo- 

 pod: Segment 1 with medial inner expansion and a very fine acces- 

 sory seta; outer spine reaching just beyond base of first spine of second 

 segment, with a broad, serrate hyaline flange. The two outer spines 

 of segment 2 subequal to one another in length, both reaching beyond 

 the end of the segment, and with serrate flanges. Beyond insertion 

 of second spine, the inner margin of segment with a cleft and a serrate 

 lappet which appears hardly separated from the anterior surface; tip 

 of segment minutely serrate. 



Left exopod : Segment 1 reduced in both width and length, with a 

 stout outer spine reaching beyond segment 2 and armed with hyaline 

 flange. Segment 2 broadened and thickened at its apex; its outer 

 spine thick and irregular, without marginal flange or serrations, 

 longer than its segment and reaching to about the same point as the 

 longest of the processes of segment 3. Segment 3 distinctly separated 

 from segment 2 on anterior side and very nearly so on posterior side. 

 Membranes folded and irregular in length and fragmentation as in 

 gracilis (figs. 33, 34). In addition to membranes, a plumose seta as 

 in gracilis, and two modified processes. Of these, one simple in 

 structure with a relatively small base, set into the segment near the 

 outer edge, not reaching beyond the membranes. The other much 

 longer, set into a well-defined socket on the inner portion of the 

 segment; protruding from near its distal end a large flattened structure 

 with hairy margins (from its position and mode of attachment this 

 process comparable to the one with flared serrate tip in gracilis). 



Right endopod elongate, reaching to near base of distal spine of 

 exopod 2, without evidence of segmentation, armed only with a 

 slender plumose seta on the outer edge. Left endopod swollen, not 

 reaching quite to end of exopod 2, without ornamentation or processes. 



RUcgewayia sp. (Torliigas) 



Figures 36, 37 



Specimens examined : 6 males, copepodid stage V. Occurring with 

 R. gracilis and R. shoemakeri, off Loggerhead Key, Dry Tortugas. 



