Anthessius — Illg 
349 
margin, except for slight notch, entire. Trim- 
erous endopodite with medial flexure. Armature: 
first segment, 1 medial seta; second segment, 
2 medial setae; third segment, 3 lateral spines 
set in steplike emarginations, 1 terminal spine, 
1 medial seta. Medial setae of distal segment 
very short. Each of basal 2 segments produced 
at distal lateral corner as small spinous cuticular 
process. Basal spine of terminal segment also 
subtended by such process. Each segment with 
row of cilia on lateral margin. Spines of ter- 
minal segment with hyaline flanges, complete 
in lateral spines, only on lateral margin of 
terminal spine. All setae of leg with plumose 
ciliation. 
Fifth legs (Fig. 21) with probably 2 seg- 
ments represented, basal consisting only of ex- 
pansion on body segment posteriorly and lat- 
erally to furnish articulation of distal segment, 
with 1 small seta representing armature. Second 
segment elongate, flattened, with cuticularized 
medial and lateral margins. Length about 1.8 
times greatest width. Armature 3 spines and 1 
seta, spines about equally spaced on lateral and 
terminal margins : 1 lateral spine at distal corner 
of lateral margin; 1 spine at about midpoint of 
broad apical margin; 1 spine at medial distal 
corner; 1 seta near medial distal spine. Seta and 
apical spine subtended by small groups of 
spinules. Spinules also forming short rows on 
distal half of medial margin and middle third 
of lateral margin. 
Sixth legs probably represented by small se- 
tiferous knob in depression at aperture of ovi- 
duct, located dorsally on lateral expansion of 
genital segment. Two subequal setules forming 
armature. 
Caudal ramus (Fig. 22) about 2.5 times as 
long as greatest width and about as long as 
anal segment. Armature 6 setae. Of apical 
quartet of setae, medial of central 2 longest, 
about 4 times as long as ramus; adjacent long 
seta 2 times length of ramus. Medial apical seta 
about .6 as long as ramus; lateral apical seta 
about .4 as long as ramus. Lateral marginal seta 
short, about .4 as long as ramus, inserted on 
lateral margin at about distal third. Dorsal me- 
dial seta very short, inserted just subapically. 
MALE (Figs. 23-26): Body length 1.5 mm., 
greatest width .5 mm., based on Wilson’s original 
description. Body very generalized cyclopoid 
in type. Cephalosome bearing first legs, its seg- 
ment indicated by slight marginal indentations. 
Metasome of free segments of legs 2 to 4. Uro- 
some of free segments of legs 5, 6, and 4 ab- 
dominal segments, including segment bearing 
anus and caudal rami. Segments of legs 5 and 
6 much coalesced in a genital complex (Fig. 
23) accommodating spermatophores which are 
very elongate. 
Antennules, antennae and mouthparts, except 
maxilliped, as in female. Maxillule (Fig. 24) of 
characteristic type of the genus; elongate, with 
shoe-shaped apex. A long medial seta and sub- 
apical spine. Two subequal small apical lobes. 
Maxilliped (Fig. 25) highly dimorphic, de- 
veloped as massive, complicated appendage, 
probably trimerous. In mouth area, maxillipeds 
held in characteristic posture, tending to align 
along longitudinal axis of body, second segment 
moving in sagittal plane over first segment, and 
terminal segment tending to swing in frontal 
plane. First segment about one-third length of 
second, unornamented. Second segment tapered 
apically, margin medial in position in normal 
posture of appendage bearing characteristic 
ornamentation, serving to act in conjunction 
with clawlike terminal segment in prehensile 
function. Medial ornamentation consisting of 2 
longitudinal multiple rows of denticles, and a 
single row of long spinules. In addition, near 
midpoint of medial margin a short, stout spine. 
Terminal segment forming very complicated 
region of articulation on apex of second seg- 
ment, prolonged as curving claw, longer than 
second segment. One seta inserted on expanded 
region of articulation. 
Dimorphism also expressed particularly in 
first legs, remaining swimming legs very sim- 
ilar to those of female. Protopodites and exo- 
podites of first legs essentially as in female. Basal 
segments of endopodites as in female, terminal 
segment of each with lateral spine, 1 apical 
spine, 1 apical seta, 3 medial setae, apical spine 
representing a seta of female appendage. 
Fifth leg (Fig. 26) not greatly like that of 
female in outline, but with similar ornamenta- 
tion. Length about 2.5 times greatest width, 
thus a much narrower appendage, without con- 
