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PACIFIC SCIENCE, VoL XI, July, 1957 
ing a variability similar to that found in 
female. Intersegmental membranes of meta- 
some segment 4 and of urosome segments 
frequently expanded as in female. Urosome 
of six segments, width decreased only slightly 
from that of fourth metasome segment. Geni- 
tal segment ventrally with pair of external 
lappets with sclerotized edges, flaplike and 
protuberant on their distal and internal mar- 
gins. Anal segment elongated as in female. 
Caudal rami divergent, with setal armature as 
in female. 
Rostrum not prominent, nongeniculate, 
appressed to ventral face or partially pro- 
tuberant in either sex. 
Antennule (Fig. 9) closely similar in male 
and female; extremely short, not equaling 
more than one-fourth of length of cephalic 
segment; 5-segmented. Second segment much 
the longest. All segments bearing non- 
plumose, thinly integumented setae; mostly 
shorter or only little longer than width of 
segment in female, relatively longer in male. 
Longest seta apical, equal to about combined 
lengths of segments 3-5. A weakly developed, 
terminally placed aesthete on segments 4 and 
5. Relative length of segments and number 
of setae (s) and aesthetes (a) : 
Segment 1 2 3 4 5 
Length 26 38 12 10 14 = 100 
Armature 3s 12s 5s 2s 7s 
a a 
Antenna (Fig. 12) alike in sexes though 
relatively larger in male than in female, its 
four segments progressively shortened from 
base to apex. Apical segment reduced to 
about half of width of third segment and 
offset laterally, bearing terminally two stout, 
clawlike setae and two slender, flexible setae 
of which the outer is much the shorter. Third 
segment bearing stout, curved claw on free 
apical portion; at its base a hairlike seta and 
small, marginal, serrate process. 
Buccal mass outwardly protuberant from 
ventral face; lab rum and its extensive frame- 
work forming anterior medial support, maxil- 
lipeds and their medial framework (Fig. 19) 
giving posterior support. Labrum united lat- 
erally with the likewise protuberant mem- 
brane of ventral face and surrounding tissue 
mass; its free posterior edge with irregular, 
sometimes bifid spinous points (Fig. 13). 
Mandible (first free appendage) entirely cov- 
ered by labrum, set in a sclerotized frame- 
work, seemingly embedded in fold of the 
lateral protruding membrane of ventral face; 
with short, stemlike basal portion to whose 
slightly enlarged, somewhat conical end is 
attached ventrally a posteriorly directed "claw” 
with distal serrate edge, and two dorsally 
arising accessory pieces— one foliate in out- 
line, the other a stout, serrate seta (Figs. 14 
and 15). First maxilla larger than mandible, 
arising laterally beyond its base; attachment 
to lateral protuberant surface membrane 
clearly distinct (Fig. 16); in situ appearing 
sinuous and elongate though actually some- 
what broadened dorso- ventrally; its margin 
faintly sclerotized (Fig. 18); bearing a single 
seta on inner posterior margin and a group of 
three apical setae. Just inside apices of first 
maxillae and immediately distad to midline of 
labrum, a pair of simple, hardly protuberant, 
unornamented lobes interpreted as parag- 
naths. These lobes partially covering anterior 
edge of distally extended structure inter- 
preted as extension of (or support of) labium 
(Fig. 19); its posterior edge supported by 
protrusion of anterior part of medial frame- 
work of maxillipeds (Fig. 19). 
Second maxilla with hugely expanded, 
membranous basal portion and simple ter- 
minal claw (Fig. 13). Maxilliped of female 
smaller but stouter in structure than maxilla, 
more or less divided into two segments, of 
which the second is the longer; armed apically 
with short, stout, curved claw. 
Oral area of male like that of female, except 
that maxillipeds (Figs. 5 and 10) more stoutly 
developed, ending in long curved claw reach- 
ing back to basal origin of appendage. 
Only two pairs of legs present in both 
sexes (legs 1, 2), much reduced in size (Figs. 
