140 
PACIFIC SCIENCE, Vol. XIV, April I960 
TABLE 1 
Variation in Proportions in the Chelae of Athanas djiboutensis Coutiere 
LOCALITY 
SEX 
CARAPACE 
LENGTH 
SMALL CHELA 
LARGE CHELA 
r? $ n 2 
S' ~ % n 
to 3 3 
8 p 5 
( in proportion to palm ) 
Merus 1/b 
Carpus 1/b 
O 
Carpus £ 
0 
Palm R 
0 
& 
Fingers .2 
g 
O) 
p 
palm) 
Merus 1/b 
Carpus 1/b 
Tahiti 
$ 
2.7 mm. 
0.8 
1.0 
1.0 
1.6 


0.4 
1.0 
0.2 
1.0 


Tahiti 
$ 
2.7 mm. 
1.0 
1.0 
1.4 
2.0 
1.6 
2.3 
0.5 
1.0 
0.2 
1.2 
3.0 
1.2 
Tonga 
$ 
3.0 mm. 
0.8 
1.0 
1.1 
1.8 
1.7 
2.7 
0.4 
1.0 
0.2 
0.9 
4.0 
1.7 
Samoa 
$ 
3.0 mm. 
0.7 
1.0 
0.9 
1.5 
2.7 
2.0 
0.4 
1.0 
0.2 
1.2 
5.0 
1.6 
Canton 
$ 
3.0 mm. 
0.8 
1.0 
2.0 
1.8 
4.0 
4.0 
0.4 
1.0 
0.2 
1.0 
2.0 
— 
Samoa 
$ 
3.4 mm. 
0.8 
1.0 
1.1 
2.0 
3.5 
2.0 
0.4 
1.0 
0.2 
1.0 
4.3 
LI 
Tonga 
2 
3.5 mm. 
0.7 
1.0 
1.2 
1.6 
3.0 
2.5 
0.3 
1.0 
0.2 
1.0 
4.6 
1.4 
Tonga 
$ 
3.6 mm. 
— 
— 
— 
— 
— 
— 
0.3 
1.0 
0.2 
1.2 
4.1 
0.7 
Samoa 
2 
2.1 mm. 
0.8 
1.0 
0.8 
1.4 
3.5 
2.0 
0.4 
1.0 
0.3 
1.0 
5.2 
1.2 
Tahiti 
2 
2.2 mm. 
0.8 
1.0 
0.9 
1.8 
3.0 
1.5 
0.4 
1.0 
0.4 
1.2 
3.0 
1.1 
Tahiti 
2 
2.4 mm. 
0.7 
1.0 
0.3 
1.2 
— 
— 
0.3 
1.0 
0.2 
1.1 
3.0 
1.8 
Samoa 
2 
2.4 mm. 
0.6 
1.0 
0.9 
1.6 
2.0 
1.6 
— 
— 
— 
— 
— 
— 
Samoa 
2 
2.4 mm. 
0.8 
1.0 
1.1 
1.6 
2.6 
2.0 
0.4 
1.0 
0.2 
1.0 
2.5 
1.1 
Tahiti 
2 
2.4 mm. 
0.8 
1.0 
1.0 
1.6 
1.3 
2.5 
— 
— 
— 
— 
— 
— 
Fiji 
2 
2.5 mm. 
— 
— 
— 
— 
— 
— 
0.4 
1.0 
0.3 
1.2 
2.2 
1.0 
Eniwetok 
2 
2.7 mm. 
0.6 
1.0 
0.3 
1.2 
2.5 
1.4 
0.3 
1.0 
0.3 
1.0 
2.2 
1.0 
Eniwetok 
2 
2.7 mm. 
0.6 
1.0 
0.6 
1.8 
2.6 
1.6 
0.4 
1.0 
0.3 
1.0 
2.1 
1.0 
Eniwetok 
2 
2.8 mm. 
0.4 
1.0 
0.3 
1.3 
3.8 
1.0 
0.4 
1.0 
0.2 
1.0 
2.4 
1.0 
Samoa 
2 
2.8 mm. 
0.5 
1.0 
0.3 
1.4 
2.8 
1.0 
0.4 
1.0 
0.1 
1.0 
2.3 
1.0 
Eniwetok 
2 
3.1 mm. 
0.4 
1.0 
0.3 
0.9 
2.4 
1.0 
0.2 
1.0 
0.1 
0.8 
2.9 
1.0 
Samoa 
2 
3.2 mm. 
0.5 
1.0 
0.2 
1.3 
2.3 
0.9 
0.3 
1.0 
0.3 
1.1 
2.0 
1.5 
Samoa 
2 
3.4 mm. 
0.5 
1.0 
0.2 
1.5 
2.6 
1.0 
0.3 
1.0 
0.2 
0.9 
2.1 
1.1 
Samoa 
2 
3.6 mm. 
0.6 
1.0 
0.2 
1.3 
2.3 
1.0 
0.3 
1.0 
0.2 
0.9 
2.1 
0.9 
Samoa 
2 
3.9 mm. 
0.6 
1.0 
0.3 
1.3 
2.4 
1.4 
0.3 
1.0 
0.2 
1.0 
2.2 
1.2 
feminine chela. This variation in the chelae is 
similar to that of other members of the genus. 
With these variations the distinctions be- 
tween the four nominal species have disap- 
peared. As the original description of A. arete- 
formis carries the description and figure of the 
characteristic chela of the male, we have chosen 
to retain that name rather than the name A. 
naifaroensis, which would have to be selected 
were strict page priority to be followed. 
DISTRIBUTION: These specimens have been 
reported from South Africa, the Red Sea, the 
Maidive and Laccadive Archipelagoes, and the 
Marianas. Specimens in the present collections 
were collected from various places on reef flats 
and fronts, lagoons, lee and windward reefs at 
varying depths. There is one specimen for Fiji, 
four from Tonga, one from British Samoa, four 
from the Cook Islands, three from the Society 
Islands, and five specimens from the Marshall 
Islands. 
Athanas djiboutensis Coutiere 
Athanas djiboutensis Coutiere, 1897. Bull. Mus. 
Hist. Nat., Paris 3(6): 233. 
Athanas sulcatipes Borradaile, 1898. Proc. Zool. 
Soc. Lond., p. 1011, pi. 65, fig. 9- 
DISCUSSION: As discussed in the introductory 
section this widespread and common species is 
quite constant in its characteristics except for 
the branchial formula and the growth and sexual 
differences of the large chela. Some minor dif- 
ferences in length of the rostrum are found, as 
was discussed for the Saipan specimens (Ban- 
ner, 1956: 322). 
In Table 1 below, the proportions of the male 
and female chelae are given for specimens taken 
at random from the collections and arranged 
according to carapace length. The changes of 
proportions with sex and growth are clearly 
shown, and the variation between specimens of 
nearly the same size does not appear to be from 
