60 PROCEEDINGS OF THE NATIONAL MUSEUM VOL. 125 
cephalothorax smooth, with slight indentation in anterior third, bearing 
narrow membrane and several hairlike processes. Posterior lateral 
region with small, cupshaped indentation. Posterior sinus (fig. 24c) 
distinct, anterior end sharply angled, lateral margins flatly concave, 
outer lateral surface bearing filmy membrane. Posterior median region 
of cephalothorax extending posteriorly well past lateral regions, pos- 
terior margin flatly convex in dorsal view; pair of minute, hairlike 
projections present, slightly anterior to posterior margin. Major 
dorsal cephalothoracic grooves forming irregular H, posterior legs 
flatly convex, anterior flatly concave, cross groove extending anteriorly 
from junction with legs of H. Ocular region distinct, in anterior 
fourth of cephalothorax. 
Free fourth pedigerous segment distinct from cephalothorax although 
anterior half overlapped by posterior median cephalothoracic region. 
Fourth pedigerous and genital segments fused dorsally and ventrally. 
Surfaces of genital segment (fig. 246) irregular; anterior region of 
segment broad, posterior bilobed, lobes extending posteriorly to caudal 
rami. Fifth legs (fig. 25g) situated on ventral surface, at beginning of 
posterior lobes, consisting of 2 nodules, anteriormost bearing single, 
lightly plumose setule, posterior bearing 2 plumose setules. 
Abdomen 1-segmented, distinct from genital segment, lateral mar- 
gins smooth, posterior margin V-shaped, almost covered by proximal 
surface of caudal rami. Caudal rami (fig. 24d) broad, lobate, width 
almost twice the greatest length. Inner surface plumose, distal surface 
bearing 3 plumose setae; inner distal surface with 1 plumose setule, 
distal outer surface with 2 plumose setules. 
Antennule (fig. 24¢) 2-segmented, attached to lateral posterior 
ventral surface of frontal region and adjacent surface of cephalothorax. 
First segment of general parallelogram shape, anterior and anterior 
ventral surface with 21 naked and lightly plumose setae and setules. 
Second segment clubshaped, length slightly less than two-thirds the 
length of anterior surface of first segment, with single naked seta from 
distal half of posterior surface, 13 naked setae from distal surface. 
Antenna (fig. 24f) 3-segmented, situated posterior and medial to 
antennule base. First segment squat, irregular, with narrow, dagger- 
like projection from posterior surface. Second segment slightly broader 
proximally than distally, distal surface irregular. Third segment and 
terminal process continuous, clawlike, with small, setule-like accessory 
process on proximal inner surface, second on medial surface. 
Ficure 24.—Caligus pseudokalumat, new species, female: a, dorsal view; c, posterior cephalo- 
thoracic sinus, same view. Ventral views: b, fourth pedigerous and genita] segments; 
d, left caudal ramus; ¢, left lunule and antennule; f, oral region, showing antenna, mouth 
cone, mandible, maxillule, maxilla base (ma-2), postantennal, and postoral processes; 
g, right maxilla; h, right maxilliped; 7, sternal furca. 
