NO. 3656 COPEPODS—LEWIS ou 
MEASUREMENTS (in mm).—16 females and 1 male: 
female 
mean range male 
Total length, excluding caudal setae 4.69 4. 00-5. 07 Ps, M5: 
Length of cephalothorax 2.78 2.45-3. 15 1. 40 
Width of cephalothorax 2.58 2. 25-3. 00 1. 35 
Length of genital segment 1.06 0. 90-1. 22 0. 38 
Width of genital segment 1.26 = 1. 05-1. 52 0. 38 
Length of abdomen 0.43 0. 30-0. 56 0.13 
Length of egg strings (12 strings) 2.66 1. 07-3. 85 
DescripTion.—Female cephalothorax (fig. 16a) ovoid, consisting 
of cephalon and first 4 thoracic segments. Frontal region narrow, 
anterior surface with slight medial indentation, with narrow mem- 
branous flange; division between frontal region and remaining cephalo- 
thorax distinct medially, indistinct laterally. Lateral margins slightly 
irregular, basically convex, with narrow membranous flange. Posterior 
sinuses distinct, V-shaped, with small membrane projecting medially 
from outer lateral surface. Posterior medial surface of cephalothorax 
with short, necklike projection forming attachment surface for free 
fourth pedigerous segment; posterior medial region extending pos- 
teriorly to posterior lateral cephalothoracic region. Major dorsal 
cephalothoracic grooves forming irregular H, anterior portion of longi- 
tudinal grooves of H terminating slightly posterior and lateral to 
ocular region. Ocular region distinct, in anterior third of cephalothorax. 
Free fourth pedigerous segment approximately twice as wide as 
long; posterior lateral region of tergum heavily sclerotized, giving 
platelike appearance. Division between fourth pedigerous and genital 
segments indistinct, incomplete. Genital segment (fig. 16c) wider than 
long, lateral margins broadly convex, posterior surface bilobed from 
dorsal viewpoint. Fifth legs (fig. 16¢) situated on posterior lateral 
ventral surface, consisting of short, spikeshaped projection bearing 
3 plumose setules dorsally, additional setule present just anterior 
to base of leg. 
Abdomen 1-segmented, short, length approximately two-thirds the 
width. Segment swollen medially, narrower at both ends. Lateral 
posterior surfaces angled posteromedially, medial region bilobed, 
forming anal opening. Caudal rami small, subrectangular, distal inner 
surface plumose. Distal surface with 3 plumose setae and 2 setules, 
one on either side of group of setae, additional plumose seta present 
on medial outer surface of rami. 
Cephalothorax of male (fig. 166) similar to that of female. Heavily 
sclerotized regions of tergum of free fourth pedigerous segment not 
extending as far posteriorly as those of female although segments 
similar. Genital segment subovoid, with slight indentation in middle 
