150 
study a single population thereby ruling out 
differences that might be caused by ecological 
or geographic races. For this reason the 15 speci- 
mens from Aitutake were studied intensively 
and those from other archipelagoes were used 
merely as supplements to the study. 
Four species closely related to A. indicus have 
been described: A. iphianassa de Man, A. am- 
boinensis de Man, A. intermedius Yu, and A. 
kominatoensis Kubo (all save the last described 
under the genus Arete). Of these, only A. am- 
boinensis appears to be distinct; it will be dis- 
cussed under A. dorsalis in the following section. 
de Man stated that his species A. iphianassa 
was similar to A. indicus, but could be distin- 
guished by the characteristics compared in the 
accompanying tabulation. 
In this series of specimens each of the criteria 
is either bridged or almost bridged: 
1 . The length of the extracorneal spines varies 
both in absolute length and in length relative 
to the eyes; both described conditions were 
found in this single series. 
2. The basal portion of the outer antennular 
flagellum is found to vary from four to six 
articles, with most having four or five articles. 
3. The carpocerite is found to vary in the 
length-breadth relationship from 1:1.5 to 1:2.7; 
some of this may be due to different rotation of 
the carpocerite itself. 
4. The outer distal margin of the outer uropod 
may be either straight or curved outward near 
the tip; all of the males have straight margins, 
but not all of the females have curved margins. 
5. Similar to the condition discussed in the 
A. iphianassa 
1. Extracorneal spines equal in length to the 
eyes. 
2. Four articles on basal portions of outer an- 
tennular flagellum. 
3. Carpocerite 1.5 times as long as broad. 
4. Outer distal margin of outer uropod straight. 
5. Various minor proportions of the large che- 
lae, but principally with that of the male 
bearing 2 teeth on the dactylus and one on 
fixed finger. 
6. Various proportions in second leg, but most 
conspicuous in the first article of the carpus 
which is 5 times as long as broad distally. 
7. Propodus of third legs bearing 8 to 12 
spines. 
PACIFIC SCIENCE, Vol. XIV, April I960 
next section for A. dorsalis, the females and the 
smaller males have straight cutting edges of 
their large and small chelae; however, the two 
intact large males have teeth developed, one 
with a single tooth on the fixed finger, none on 
the dactylus, the other with two teeth on the 
fixed finger and one on the dactylus. 
6. The proportions of the carpal articles of 
the second legs are extremely variable, with the 
first article varying from 1.4 to 3.0 times as long 
as broad distally; in some, also, the first article 
is approximately equal in length to the sum of 
the following carpal articles, in others it is al- 
most twice as long. 
7. The spines on the propodus of the third 
legs vary in number from four to nine, and also 
in development, with some scarcely more than 
slight hairs, and others strong and well de- 
veloped. 
Also like A. dorsalis the development of the 
rostrum varies conspicuously. In one specimen 
the tip reaches beyond the end of the third an- 
tennular article, in four it reaches some distance 
along the third article, in eight it reached some- 
where in the length of the second article (most 
to near the tip of the article) and in one it 
reaches only to the end of the first article. 
The other specimens in the collections avail- 
able, including those reported from Saipan as 
Arete iphianassa (Banner, 1956: 325), fall 
within the range of variation reported above 
with the exception of three fragmentary speci- 
mens from Canton Island. These three, unfortu- 
nately mostly without legs and with but two 
chelae among them, all have slightly different 
A. indicus 
1. Extracorneal spines slightly longer than the 
eyes. 
2. Six articles in same. 
3. Carpocerite 3.0 times as long as broad. 
4. Outer distal margin of outer uropod curved 
outward. 
5. Fixed finger of large chela of male bearing 
1 tooth, dactylus curved but unarmed. 
6. First carpal article 3 times as long as broad 
distally. 
7. Propodus of third legs bearing two to three 
spines. 
