CRUSTACEA OF THE MERGUI ARCHIPELAGO. 113 
euished from G. Dussumiert, at first sight, by the somewhat 
different shape of its carapace, especially by the different 
direction of its margins. Although G. arcwatus has been found 
in the seas of Japan and New Caledonia, it has not yet been 
recorded from the Indian Ocean. 
Gelasimus Dussumierit has been recorded from Zanzibar, the 
coast of Malabar, Java (Samarang), and from New Caledonia; so 
that it seems to be distributed throughout the whole Indian 
Ocean and the Malayan Archipelago. 
The collection of the Leyden Museum contains specimens 
from Nossy-Faly (near Madagascar), which have been described 
by Hoffmann (Crustacés de Madagascar, 1874, p.17); but as 
they differ only from the type of G. Dussumiert in the mero- 
podites of their ambulatory legs being slightly more enlarged, 
and in the joints of these appendages being a little less slender, 
I regard them only as a local race, or possibly individual varieties 
of this species. 
72. GELAsIMuUS acurus, Stimps. (Pl. VII. figs. 8 & 9, and 
Pl. VIII. figs. 1-4.) 
Gelasimus acutus, Stumpson, Proceed. Acad. Nat. Sci. Philadelphia, 
1858, p. 99. 
No fewer than sixty-six specimens were collected, namely 
forty-eight males and eighteen females. Of forty-six specimens 
the exact locality is not indicated; the others are from the fol- 
lowing localities : twelve from Kisseraing, three from King Island, 
two from Zediwon on the Tenasserim river, two from the bank of 
Rangoon river, and one from Tavoy. 
This species belongs to the same section of the genus as the 
last. It was discovered by Stimpson off the coast of China, near 
Macao, and was established by him for the reception of an im- 
mature individual, in which the distance between the external 
orbital angles measured nearly 18 millim., the length of the cara- 
pace 10 millim., and that of the larger hand about 22 millim. 
Specimens from the Mergui Collection which present these 
dimensions fully agree with Stimpson’s diagnosis. 
Gelasimus acutus is most closely allied to G. Dussumieri, espe- 
cially in the shape of its carapace, but it may be distinguished by 
the form of the median frontal furrow and at first sight by the 
LINN. JOURN.—ZOOLOGY, VOL. XXII. 8 
