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PACIFIC SCIENCE, Vol. VII, January, 1953 
tennae, mouthparts (with the exceptions 
noted below); small chela (the large chelae 
were lacking in Coutiere’s specimens), second 
and following legs, including the important 
dactyli; and the peculiar pleopods of the 
male and female. Even the tendency toward 
protuberant eyes, noted above, was found in 
Coutiere’s specimens, as in the plate the me- 
dial portion of the eyestalks appears beyond 
the anterior margin of the carapace. 
C. nanus differs from Coutiere’s specimen in 
the rostrum, which is poorly demarked lat- 
erally even at the edge of the carapace and 
which has its tip depressed in lateral view; 
in the endopod of the third maxilliped, in 
which the basal article is narrower, the second 
article broader, and the third article bearing a 
distal tuft of setae; and in the small chela, 
which lacks spines on the lower margin of the 
palm. In Alpheus sp. the rostral ridge is still 
discernible between the orbital hoods, the 
rostral tip is not depressed, and the palm of 
the small chela bears five {}) spines on its in- 
ferior margin. When the wide range of varia- 
tion in the closely related C. paragracilis is 
considered, these minor differences certainly 
do not appear to be of specific worth. 
The possibility suggested by Coutiere that 
C. nanus is a synonym of C rostratipes (Po- 
cock) can be ruled out. In the first place, Po- 
cock’s specimen came from Eernando Noron- 
ha in the Atlantic Ocean off Brazil; while this 
does not exclude the possibility that the two 
species are identical, it certainly reduces the 
probability, for almost no species of this 
genus found off the Atlantic coast of the 
Americas is also found in the Indo-Pacific 
area. Anatomically, several characters separate 
the species in spite of the fact that Pocock 
published only a short description without 
plates : C. rostratipes is described as having the 
rostrum "springing from center of a depres- 
sion,’’ which certainly could not be applied to 
the Hawaiian form; the articles of the anten- 
nular peduncle are described as being equal 
in length, whereas in C. nanus the third article 
is the longest; the merus of the small chela is 
described as having the superior margin pro- 
duced into a "conspicuous tooth,’’ a descrip- 
tion that would not suit the subacute projec- 
tion of this species; finally, the articles of the 
carpus of the second legs in C rostratipes have 
the ratio 10 : 5 : 2 : 3 : 4, instead of 10 : 6 : 
4:3: 8. 
Returning to the contention of Coutiere 
that his specimen may represent a distinct new 
genus, he states: 
Volume des fouets antennaires et de I’antenne, incom- 
plete protection des yeux, volume du labre, forme tres 
speciale des mandibules, du 2® maxillipede, du 3® max- 
illipede, des pinces de la 1® paire (?), brievete de la 
2® paire, reduction du nombre des epipodites, forme 
tres speciale des pleopodes, tels sont les caracteres que 
Ton pourrait invoquer pour la separation de I’A. rostra- 
tipes et des formes affines. Le nouveau genre pourrait 
recevoir le nom de Metalpheus s’il etait conserve. 
The prime basis for separation, not empha- 
sized in this paragraph, was the supposition 
of Coutiere that the large chela (lost in his 
specimens) was similar in form to the small 
chela. This was an erroneous assumption. 
Of these characteristics, all save the short- 
ness of the second thoracic legs and the modi- 
fied pleopods are found in C. paragracilis as 
well as C. nanus. The similarity of the two 
species, as pointed out above, is especially 
marked in the peculiar mouthparts and bran- 
chial formula. This relationship is so close 
that C. paragracilis and C. nanus must be in- 
cluded in the same genus. However, as C. 
paragracilis shows definite affinities to other 
members of the genus Crangon, I do not be- 
lieve that the erection of the proposed genus 
would be justified. 
distribution: Most of the specimens of 
this species came from coral heads in water 
10-20 feet deep immediately outside the shal- 
low portions of the reef. The few specimens 
from near the intertidal zone were collected 
at the following places: from algal holdfasts 
at Kawela Bay and on the open coast east of 
Koko Head, on Oahu; from coral at Kalama 
Park and at Lahaina, on Maui. The specimens 
from deeper water came from the following 
localities: off Mokulua Islands, Hanauma 
Bay, Waikiki Reef, and Nanakuli, on Oahu; 
