132 
PACIFIC SCIENCE, VoL VII, January, 1953 
per and lower margins and margins of op- 
posing faces of fingers. Carpus O'. 2 5 as long 
as chela, 1.2 times as long as broad. Merus 
similar in form to that of large chela but 
without terminal tooth on inferior internal 
margin, with 4 small movable spines instead. 
Small chela of male 3.7 times as long as 
broad, fingers occupying slightly more than 
0.6 length of chela. Dactylus not rounded, 
but with opposing face flattened, with short 
dense fringe of stiff setae along margins of 
face in middle 0.7; fixed finger also flattened, 
with corresponding fringe of setae in opposi- 
tion; other setae similar to those of female. 
Carpus and merus in male similar to those of 
female. 
Carpal articles of second legs with ratio 
10 : 23 : 7 : 10 : 11. 
Ischium of third legs with strong movable 
spine. Merus 4.0 times as long as broad, 
inermous with occasional short setae. Carpus 
0.5 as long as merus, distal angles not pro- 
jecting but rounded; superior margin with 
series of long setae. Propodus 0.6 as long as 
merus, tapering toward tip, straight, with 7 
movable spines of moderate size, with nu- 
merous long setae on both margins, some of 
setae 0.5 as long as article. Dactylus long, 
simple, almost 0.3 as long as merus, superior 
margin rounded, inferior margin broad and 
flattened, somewhat curved; tip acute; lateral 
margins with short movable spine and short 
curved bristle. 
Telson with anterolateral margin convex, 
broadest at about 0.3 of length, posterolateral 
margin concave and narrowing; 1.8 times as 
long as broad, tip 0.7 as broad as maximum 
breadth. Posterior margin strongly arcuate, 
reaching beyond tip of posterolateral spines. 
Posterolateral spines about 0.3 as long as 
breadth of tip; dorsal spines poorly developed, 
located 0.4 and 0.6 of distance from articula- 
tion to tip. Tip of telson and distal lateral 
margin of inner uropod with weak spinules. 
Body translucent white to gray base color, 
with red and blue chromatophores arranged 
in poorly defined transverse bands on abdo- 
men and in narrow band across eyes; similar 
poorly defined bands on chelae. In one live 
specimen blue chromatophores expanded, 
giving over-all blue-gray appearance; in other, 
red chromatophores expanded, giving reddish 
cast. 
DISCUSSION: No significant variation was 
noted in the three specimens. 
RELATIONSHIP: This species plainly belongs 
to the Brevirostris Group and can be separated 
easily from all other Hawaiian species save 
C. rapax (Fabr.) by the appearance of the 
anterior margin of the carapace, the com- 
pressed chela with a transverse groove, and 
the dactylus of the third legs. 
Within the Brevirostris Group this species 
and C. sauvensis (de Man) can be distinguished 
by the characteristics given in de Man’s key 
(1911: 322-325). From most of the other 
species in the group these two can be dis- 
tinguished by the following characters: the 
presence of a transverse groove on the palm 
of the large chela; the balaeniceps-shaped 
dactylus of the small chela of the males; the 
lack of a tooth on the merus of the third leg. 
Three more closely related species, C. djedde fi- 
sts (Coutiere), C. djihoutensis (de Man), and 
C. pubescens (de Man), all have a longer and 
thinner merus on the third leg; in addition 
C. djeddensis has a transverse groove on the 
third chela; in C. djihoutensis the terminal spine 
of the scaphocerite is much longer relative to 
the squamous portion; and in C. pubescens the 
rostral carina is longer. 
C. platyunguiculata can be separated from 
C. sauvensis by the characteristics given in the 
following tabulation: 
C. platyunguiculatus 
Rostrum reaching beyond 
orbital hoods by 0.5 its 
length 
Stylocerite with tip 
straight 
Scaphocerite shorter than 
carpocerite 
C. sauvensis 
Rostrum reaching beyond 
orbital hoods by 0.8 its 
length 
Stylocerite with tip in- 
curved 
Scaphocerite as long as 
carpocerite 
Large chela with palm 2.0 
times as long as fingers 
Carpal articles of second 
legs with ratio 10 : 23 : 
7 : 10 : 11 
Large chela with palm 1.5 
times as long as fingers 
Carpal articles of second 
legs with ratio 10 : 15 : 
6 : 6:6 
V 
