CRUSTACEA OF THE MERGUI ARCHIPELAGO. 179 
parallel to the frontal margin; in 8. bidens, S. Haswelli, and 
S. guttata, on the contrary, they appear to be directed obliquely, 
forming an angle with the frontal margin, when the hands are in 
the same position. The distal row is composed of 18-22 teeth, 
the other of asomewhat smaller number. The mobile finger is less 
granular externally than in S. bidens, presenting some granules 
only at the base; it is covered on its upper margin with a 
row of 12 or 13 transverse prominences, which differ much in 
form from those of Sesarma bidens and S. guttata. They are 
scalariform, and closely resemble those of S. Haswelli, each pro- 
minence being flattened above and more or less declivous at 
its distal margin; in S. Dussumiert, however, they are com- 
paratively larger than in S. Haswelli, as well as fewer in number. 
The granules on the proximal half of the finger, at the inner 
side of the row of prominences, are more acute in S. Haswelli 
than in the other species, and nearly subspiniform. The inner 
surface of the mobile finger is smooth, that of the immobile finger 
rather granular. 
The ambulatory legs resemble closely those of Sesarma bidens, 
but the dactylopodites are a little longer in proportion to the 
propodites, the proportion of the propodites to the dactylopodites 
of the penultimate pair being in S. Dussumieri as 8: 7, in SN. 
bidens as 8 : 6. 
Dimensions :— 
millim 
Distance between the extraorbital teeth ........ 213 
Length of the cephalothorax .................. 183 
In a typical specimen from the Paris Museum these numbers 
are respectively 30 and 253. 
Sesarma Dussumiert has hitherto been recorded from Bombay ; 
it thus inhabits the northern part of the Indian Ocean. 
98. SrsaRMA Livipa, dA. W.-Hdw. 
Sesarma lividum, Alph. Milne-Edwards, Nouv. Archives du Muséum 
Hist. Nat. t. v. Bulletin, p. 25 (1869), and t. ix. p. 308, pl. xvi. fig. 2 (1873). 
Seven young male specimens were collected—three from the 
mangrove-swamps at Zediwon, one from Kisseraing, and three 
specimens elsewhere. These I refer with some doubt to this 
species. 
Sesarma livida is the fifth species of this section of the 
genus, and has hitherto been known only from the seas of New 
Caledonia. It is closely allied to the four other representatives 
of this section mentioned above. Its cephalothorax resembles so 
12* 
