PARASITIC COPEPOD CRUSTACEANS — LEWIS 113 



partially covered by second, slightly more than twice as wide as 

 long, rounded posteriorly, without winglike extensions. Fourth pe- 

 digerous segment with large, posteriorly bilobed ala covering anterior 

 end of genital segment, sinus between lobes deep, similar to that of 

 Dinematura latifolia. 



Genital segment (fig. 24c) distinct from fourth pedigerous segment, 

 with 2 lobate posterior projections formed as extensions of pair of 

 longitudinal swellings extending most of dorsal length of segment. 

 Median posterior sm-face forming place of attachment of orbicular 

 plate (sixth segment of Wilson, 1907b) extending posteriorly ventral 

 to lobate posterior projections of segment. Fifth leg (fig. 24(/) a 

 minute, lobate projection from lateral ventral surface anterior to 

 seminal receptacles, bearing 2 plumose setules. Abdomen (fig. 24c) 

 1 -segmented, attached to slight swelling on ventral surface of genital 

 segment, just posterior to seminal receptacles (each receptacle bear- 

 ing large club-shaped spermatophore) . Caudal rami (fig. 24c) large, 

 laminate, with 4 pliunose setae from posterior margin in addition 

 to 2 setules, 1 on either side of group of setae. 



Antennule (fig. 25a) 2-segmented, attached to lateral ventral 

 cephalothoracic surface just posterior to division between cephalo- 

 thorac and frontal region. First segment approximately one and two- 

 thirds the length of second, slightly broader proximally than distally, 

 appearing twisted so that anterior surface forms ventral sm-face 

 distally, surface bearing approximately 22 setules and plumose setae. 

 Second segment elongate, distal end with approximately 8 naked 

 setules. Antenna (fig. 256) indistinctly 3-segmented, poorly devel- 

 oped, attached medial and posterior to antennule base. First and 

 second segments forming club-shaped structure, segments partially 

 fused, division incomplete, visible at base of swollen distal end of 

 club-shaped formation. Swollen end with irregular, narrow, platelike 

 regions of heavy sclerotization that form adhesion surface. Third 

 segment and terminal process claw-shaped. Mandible (figs. 25c, d) 

 long, rodlike, articulating in plate-shaped region of heavy sclerotization 

 closely associated with plate forming base of postoral process. Distal 

 region of mandible not curved although slightly flattened, inner margin 

 with 12 denticulations. Postantennular adhesion pad (fig. 25a) ir- 

 regularly ovoid, with indistinct ridges. Postoral process (figs. 25c, e) 

 elongate, lateral margins irregular, with small, 2-parted, conical sub- 

 terminal process. Postoral adhesion (fig. 25c) pads elongate, situated 

 at anterior medial end of region of heavy sclerotization associated with 

 maxilla and maxilliped bases. Maxilla (fig. 25e) 2-segmented, first 

 segment slightly longer than second and larger, second segment 

 narrow proximally, flaring distally, distal end bearing 2 saber-shaped 

 terminal processes and tuft of plumosities between processes. Inner 



