PARASITIC COPEPOD CRUSTACEANS — ^LEWIS 125 



Measurements. — Nine female specimens: 



Greatest length, excluding setae 



Greatest length of cephalothorax 



Greatest width of cephalothorax 



Greatest length of fourth pedigerous segment 



Greatest width of fourth pedigerous segment 



Greatest length of genital segment 



Greatest width of genital segment 



Greatest length of abdomen 



Greatest width of abdomen 



Length of egg strings 



Diagnostic description of female. — Cephalothorax (figs. 31 a, 6) 

 suborbicular, consisting of cephalic, maxilliped-bearing and first 2 

 pedigerous segments. Frontal region broad, with narrow membrane 

 on anterior margin; lateral cephalo thoracic margins convex, bcrdered 

 by narrow membrane. Posterior end of lateral cephalothoracic re- 

 gions sharply curved, inner margin free at distal end of legion, attached 

 to lateral margin of second pedigerous segment for most of its length, 

 line of division between second pedigerous segment and rest of cepha- 

 lothorax convex. Major dorsal cephalothoracic grooves extending 

 anteriorly and slightly laterally from division between second pe- 

 digerous segment and rest of cephalothorax, terminating in anterior 

 third of cephalothorax. Several short grooves present, projecting 

 medially from irregularities of lateral cephalothoracic margins. 

 Groove separating second pedigerous segment forming, with major 

 dorsal cephalothoracic grooves, hregular H, similar to that of caligids. 

 Second pedigerous segment broad, width more than twice the length, 

 lateral regions projecting laterally and cmwing posteriorly, with 

 membrane on inner margin of posteriorly curved portion (fig. 316). 

 Inner margin of segment forming, with outer margin of free thhd 

 pedigerous segment, distinct sinus. 



Third and fourth pedigerous segments (fig. 316) free, width of third 

 more than 3 times the length, separated from second pedigerous 

 segment by flatly convex line of division dorsally. Lateral surfaces 

 of segment irregular dorsally, forming, knob-shaped structure ven- 

 trally, similar to that found in Dinematura latifolia. Fourth pedig- 

 erous segment distinct from third, swollen at region of fourth leg 

 attachment. Division between fourth pedigerous and genital seg- 

 ments incomplete, visible on ventral and lateral surfaces but not on 

 dorsal surface. 



Genital segment (fig. lie) variable in shape, dependent upon egg 

 content, broader posteriorly than anteriorly, anterior region forming 

 posterior portion of necklike connection between fom"th pedigerous 

 and genital segments. Lateral posterior margin of segment with 3 



