350 
PACIFIC SCIENCE, Vol. IX, July, 1955 
Body flattened, 8.8 mm. X 4.2 mm., 
brownish in alcohol. 
Carapace orbicular, slightly wider than long 
including lateral lobes, and less than half as 
long as entire body. Front prominent, trian- 
gular, two sides widely round, with a slight 
notch about the middle and hind border hori- 
zontal. Frontal plates well developed, four 
fifths as wide as carapace, with a distinct 
median incision and round lateral ends. Pos- 
terior lobes linguiform, blunt, scarcely attain- 
ing hind border of third thoracic segment. 
Longitudinal sutures on dorsal face parallel, 
their anterior ends far from reaching the front 
of carapace. Eye inconspicuous. 
Second to fourth thoracic segments dis- 
tinct. Second segment more than two thirds 
as wide as carapace, one fifth as long as its 
own width, with reentrant, arcuate hind bor- 
der, and with quadrate lateral plates, extend- 
ing outwards and backwards; apices of plates 
truncate and partly concealed beneath pos- 
terior lobes of carapace. Third segment lenti- 
form, as long as, but narrower than, preceding 
segment, into whose posterior excavation it 
is fitted. Fourth segment contracted in front 
into a short narrow neck and expanded in the 
rear into a pair of circular dorsal plates cov- 
ering anterior end of succeeding segment; the 
plates separated from each other by a median 
sinus. Width of the segment across the plates 
a little greater than that of third segment, 
length including the plates a little less than 
that of second and third segments combined. 
Genital segment strongly inflated, with length 
equal to that from the front of carapace to the 
end of third segment, three fourths as wide 
as long, elliptical in outline, with gracefully 
curved sides, but trilobed at the hind end by 
a pair of deep longitudinal incisions. Median 
lobe of this end with a horseshoe-shaped out- 
line, much wider than triangular lateral ones, 
and extending back beyond these. Sides of the 
segment curled ventrally, forming narrow 
longitudinal flaps. Abdomen about two sev- 
enths as long as genital segment, more than 
half as wide as long, somewhat narrowed at 
anterior end. It is attached to ventral surface 
of genital segment a short distance behind 
the center, so as to be entirely concealed in 
a dorsal view. Egg strings folded several times 
on either side of abdomen. 
First antennae with basal joint relatively 
narrow, thickly covered with plumose spines 
on distal portion; apical joint filiform, with 
simple spinules. Second antennae with an 
oval boss at the base, claw with its tip dam- 
aged in the present specimen, but retaining 
two spinules. Mouth tube elongate conical, 
enclosing styliform mandibles. First maxillae 
transformed into obovate corrugated bosses, 
close to the bases of first antennae. Second 
maxillae indistinctly two jointed; basal joint 
elongate, apical joint short, standing at right 
angles to the basal and tipped with a short 
spine. First maxillipeds have two unequal 
claws, doubly edged with narrow pectinate 
rim, near the base of claws, a hemispherical 
boss, thickly covered by fine cirri. Palm of 
second maxillipeds massive, bearing a short 
dactyliform basal process; finger broken. A 
pair of fusiform corrugated bosses present on 
the sternum in the region just in front of the 
bases of the named limbs and on either side 
of the midline. 
Four pairs of legs biramose, with rami 
fringed with well-developed plumose spines 
in all. Both rami two jointed in first pair, 
three jointed in succeeding two, inner mem- 
ber two jointed, and outer member three 
jointed in fourth. Protopodites of both sides 
widely separated from each other in first and 
last pairs, rather small in first, but strongly 
dilated in last. They are fused together form- 
ing a wide apron in other pairs. Arrangement 
of spines on the legs is given in Table 1. 
First legs with anterior face of protopodite 
with very fine, parallel striations. Second legs 
with bosses covered with similar striations 
on basal apron, two on anterior face and one 
on posterior face on each side. Third legs 
