PARASITIC COPEPOD CRUSTACEANS — LEWIS 69 



covering dorsal and lateral surfaces and projecting ventrally below 

 ventral surface of body as well as posteriorly, over free pedigerous 

 segments. 



Although fu'st pedigerous segment considered fused with ceph- 

 alothorax, indistinct indication of anterior margin present as inverted, 

 V-shaped region of heavy sclerotization between and slightly posterior 

 to maxilliped bases. Second and thu*d pedigerous segments narrow, 

 appearing ringlike from ventral viewpoint. Single pair of plates or 

 elytra present on second pedigerous segment, arising from ventro- 

 lateral, lateral, and dorsal sm*face, projecting posteriorly well past 

 posterior end of carapace-like cephalothoracic covering. Surface of 

 elytra similar to that of thoracic legs, covered with minute, knoblike 

 regions of heavy sclerotization and margined by minute denticulations. 

 Status of fifth thoracic segment (= fourth pedigerous segment if 

 legs were present) uncertain; Shiino (1955c) indicates it is fused with 

 the genital segment but specimens examined for this description 

 indicate that although it is coalesced posteriorly and separable from 

 the genital segment only by an indistinct, incomplete line of division, 

 it does project slightly and is similar to the preceding 2 segments. 

 This segment fits into an indentation in the anterior end of the 

 genital segment and is partially or completely covered by the swollen 

 genital segment (fig. 4e) . 



Genital segment (fig. 4:g) swollen, lateral margins smoothly bi- 

 concave, posterior margin flatly rounded dorsally, irregular ventrallj^, 

 segment overlapping abdomen laterally and dorsally. Abdomen 

 1-segmented, irregular, norrower anteriorly than posteriorly although 

 posterior end slightly swollen, with hea\dly sclerotized band around 

 posterior margin. Proxmial ends of caudal rami forming segment-like 

 structure, inner surfaces V-shaped and forming tubelike extensions of 

 proctodaeum. Distal half of each ramus narrower than proximal, 

 from dorsal viewpoints, inner lateral surface convex. Outer medio- 

 lateral surface, dorsal surface, and ventral surface with row of 

 spikelike processes that barely break through cuticle, distal end of 

 ramus with concentration of processes, giving thorny appearance 

 (fig. 5a). 



Cephalothorax of male (figs. 4c, d) sunilar to that of female. Free 

 pedigerous segments larger; second pedigerous segment and part of 

 thu'd covered dorsally by carapace-like cephalothoracic covermg. 

 Second and thu"d pedigerous segments short, disk-shaped from ventral 

 viewpoint, each with platelike cuticle dorsally, extending posteriorly 

 over part of succeeding segment. Second pedigerous segment without 

 elytra present in female. Fifth thoracic segment mcompletely fused 

 with genital segment, division apparent as irregular, mcomplete groove 

 and line of heavier sclerotization; segment covered dorsally by plate- 



