PARASITIC COPEPOD CRUSTACEANS — LEWIS 75 



Distribution. — Kermadec Islands, Cape Verde Island, Gulf of 

 Mexico, Japan, Hawaii, eastern Pacific. 



Material.— Thirteen adult females (USNM 110803) taken by 

 E. C. Jones and Kenneth Sherman from the external surface of a 

 specimen of Prionace glauca captured by longline at 40°15'N., 

 170°16'W. Although this is far removed from the Hawaiian Islands, 

 the species is included here because of the frequent occurrence of 

 Prionace glauca, the principal host (Cressey, in correspondence), 

 around the Hawaiian Islands (Gosline and Brock, 1960) and the 

 report of the copepod from the Hawaiian Island region by Wilson, 

 (1907b, 1924b). 



Measurements. — Thirteen female specimens: 



mean (mm.) rangeimm.) 

 Greatest length 



Greatest length of cephalothorax 

 Greatest width of cephalothorax 

 Greatest length of genital segment 

 Greatest width of genital segment 

 Greatest length of anal lamina (12 specimens) 

 Greatest length of caudal ramus 

 Length of egg string (5 specimens) 



Diagnostic description of female. — Cephalothorax (fig. 7a) 

 consisting of cephalic, maxilliped bearing and first pedigerous seg- 

 ments, narrower anteriorly than posteriorly, greatest length slightly 

 more than greatest width. Lateral margins flatly convex, with nar- 

 row, denticulated membrane along anterior portions; posterior mar- 

 gin irregularly concave, median half irregularly denticulated. Frontal 

 region narrow, with distinct median depression between incompletely 

 fused frontal plates, each frontal plate with dark brown to black 

 ovoid area of pigmentation. Second, third and fourth pedigerous 

 segments incompletely fused ventrally, distinguished dorsaUy by 

 plates arising as extensions of tergites. Second through fourth pe- 

 digerous segments (fig. 7b) each with median plate, that of third more 

 than twice the length of second, with median sinus posteriorly, that 

 of fourth approximately one and two-thirds the length of thu^d, with 

 median sinus posteriorly. Second pedigerous segment also with pan* 

 of plates originating lateral to median plate, extending laterally and 

 posteriorly on dorsal surface and anteriorly underneath posterior 

 lateral cephalothoracic region to form large, ridged adhesion pad 

 (fig. 7c). Plate of fourth pedigerous segment overlapped anteriorly 

 by plate of third pedigerous segment and overlapping anterior 

 half of genital segment. 



Genital segment (fig. 7c) broader anteriorly than posteriorly, lateral 

 margins flatly convex in anterior two-thirds of segment, sharply concave 



