PUERTO RICAN COPEPODS — GONZALEZ AND BOWMAN 265 



terminal segment with setae only at apex, Md usually well developed. 

 Mx2 with large basal segment bearing at most 3 endites. Mxp very 

 characteristic; 3-segmented; middle segment usually long. Re of 

 Pi 3-segmented, without inner seta on Rel ; Ri sometimes prehensile 

 and 2-segmented, usually nonprehensile and 3-segmented. P2-P4 

 usually with 3-segmented rami; Ri sometimes 2-segmented. P5 

 similar in male and female, 2-segmented; medial lobe of segment 1 

 with 2 apical setae. 1 egg sac. 



Genus Microsetella Brady and Robertson 



Body fusiform, compressed laterally. Rostrum short, immobile, 

 bent ventrad, and not visible from above. Caudal rami short, the 2 

 middle terminal setae very long. Female Al 6-segmented; segment 3 

 elongate. Re of A2 3-segmented. Md well developed; gnathal lobe 

 with few teeth; Re very small; Ri large, with single enlarged seta on 

 middle of inner margin. Re and Ri of P1-P4 3-segmented; Ri longer 

 than Re. P5 of female foliaceous; distal segment with 3 marginal and 

 1 surface setae. 2 species. 



Microsetella norvegica (Boeck) 



Figures 16ii-e 



Setella norvegica Boeck, 1865, p. 281. 



Microsetella norvegica (Boeck).— Wilson, 1932a, p. 38; 1932b, pp. 176-177, fig. 

 21.— Lang, 1948, pp. 230-232, fig. 122-1 [synonomy, literature, distribution].— 

 Carvalho, 1952, p. 155, pi. 2, figs. 47-50.- Deevey, 1952b, p. 146; 1956, 

 p. 139.— Fish, 1955, pp. 242-249 [life history]. 



Microsetella atlantica Brady and Robertson. — Cleve, 1900, pp. 69-70, 



Female. — Longest caudal seta about as long as body; next longest 

 about as long as urosome. Medial seta on inner lobe of segment 1 of 

 P5 about half as long as outer seta. Length 0.35-0.53 mm. 



Male.— Smaller than female; length 0.33-0.42 mm. P5 much 

 reduced. 



Distribution. — A eurythemic and euryhaline species, widely 

 distributed in all oceans. In the Puerto Rican collections it was 

 taken on the shelf but not in the bays. 



Order Cyclopoida 

 Family Corycaeidae 



Prosome cylindrical or conical, 2-4-segmented. Head with pair of 

 prominent ocular lenses located close together, sometimes contiguous. 

 Posterior corners of PedSeg 3 and usually PedSeg 4 produced into 

 points. PegSeg 5 very short. Urosome 2-3-segmented, Caudal 

 rami usually narrow and long, with 3 terminal and 1 lateral setae. Al 



