163 
Alpheids from Onotoa — Banner 
Alpheus Fabricius 
Megacheles Group 
Alpheus oahuensis Banner, 1953 
Fig. 3 
For synonymy see Banner, 1956. 
locality: 1 specimen at GOC-51. 
discussion: It is with considerable doubt 
that this specimen, all mm. male, is assigned 
to this species. The rostral front, assymetric- 
ally developed in this specimen, is the same 
as that of A. oahuensis , but the articles of the 
antennular peduncles are shorter and rela- 
tively broader. The merus of the large chela 
is also slightly heavier, and the tooth on the 
distal inferior margin is rounded and without 
an acute tooth. The chela itself is of the same 
basic form, but more slender in this specimen, 
and the teeth flanking the articulation of the 
dactylus are not as well developed. In the 
small chela the greatest differences occur, for 
there the fingers are equal in length to the 
palm, instead of being 1.4 times as long, and 
are not thin and markedly curved, and do not 
bear the rounded ridge like those of A. oahuen- 
sis. The second legs are lacking. In the third 
legs the armature is similar but the legs are 
thinner, with merus 6 times as long as broad 
instead of 3.4 times; the inferior unguis of the 
dactylus is smaller. 
But in spite of these differences in propor- 
tion, the general appearance of the two forms 
is quite similar, and these differences may be 
due to growth differences, for the type is 27 
mm. long. Moreover, some variation along 
these lines was found in the paratypic series 
from Hawaii. However, with only one speci- 
men from Onotoa, it is impossible to decide 
whether these differences are from individual 
variation, or from growth, or are constant 
differences that would be worth subspecific 
or specific rank. 
Alpheus collumianus medius Banner, 1956 
For synonymy see Banner, 1956. 
locality: 2 specimens at GOC-51. 
Machrochirus Group 
Alpheus gracilis var. simplex 
(Banner), 1953 
For synonymy see Banner, 1956. 
locality: 1 specimen from GOC-51. 
discussion: This single specimen agrees 
Fig. 3. Alpheus oahuensis (Banner), a , Anterior region; h , large cheliped; c, small cheliped; d , dactylus, third legs. 
