CRUSTACEA OF THE MERGUI ARCHIPELAGO. 119 
developed, the inner margins of the fingers are not armed with 
the three or four prominent teeth which occur in the type, but 
present only some small equal granules, especially in their distal 
halves. 
This common Indian species has been collected throughout the 
whole Indian Ocean, the Malayan Archipelago, and the Pacific 
Ocean, having been recorded from Zanzibar, Mozambique, Nossi- 
Bé, Madras, Ceylon, Nicobar Islands, Java, the Philippines, 
Moluccas, New Guinea, the Fiji Islands, and Tahiti. 
74, GELASIMUS TRIANGULARIS, A. W.-Hdw. (Pl. VIII. figs. 
8-11.) 
Gelasimus triangularis, Alph. M.-Edwards, Crustacés dela Nouv. Calé- 
donie, Nouv. Arch. du Muséum Hist. Nat. t. ix. p. 275. 
Gelasimus perplexus, Heller, Crustaceen der Novara-Reise, p. 38, Taf. v. 
fig. 4 (nec Milne-Edwards). 
Thirty-three specimens (24 3, 9 2) were collected, five of 
which were found at Kisseraing Island, the other specimens 
being without a definite locality. 
This form belongs to the same section of the genus as the 
preceding species. In the shape of its cephalothorax it stands 
in the same relation to Gelas. annulipes, M.-Hdw., as Gelas. acutus, 
Stimps., does to Gelas. vocans, M.-Edw. The carapace of Grelas. 
acutus is much more narrowed behind than that of Gelas. vocans, 
and the cephalothorax of Gelas. triangularis is much more 
narrowed posteriorly than that of Gelas. annulipes. 
The specimens have been compared and identified with a 
typical specimen of G. triangularis from New Caledonia, in the 
Paris Museum. 
I will now describe this species and compare it at the same 
time with Gelas. annulipes. The cephalothorax is strongly 
convex and arcuate longitudinally, and much larger in front than 
at the posterior margin. ‘The upper surface appears perfectly 
smooth and presents no interregional grooves, so that the grooves, 
which in G. annulipes separate the gastric from the branchial 
and cardiac regions, are absent in this species. The median 
frontal groove is also scarcely visible and less distinct than 
in G. annulipes. As regards the shape of the front, both 
species agree with one another; in both it appears a little puinc- 
tate when examined under a magnifying-glass. 
