1900.] A. Alcock — Carcinological Fauna of India. 409 



half of the posterior border of the meropodite, and in the first 3 pairs 

 there is a smaller subterminal spine on the anterior border of the same 

 joint. The 2nd and 3rd -pairs of legs are about If times, the 1st pair 

 are not quite If times, and the 4th pair are about 1J times the length 

 of the earn pace. 



Colour mottled dark green. A single female was found clinging to 

 the floats of a fisherman's net in the R. Ichamutty above Bongong in 

 the Jessore District: its carapace is 15 millim. long and 19 millim. 

 broad. 



The legs are obviously adapted for swimming, and the recurved 

 dactyli and spiny meropodites appear to be adaptations to a swift 

 current. 



The chief difference between this species and P. deianira — the female 

 of the former being compared with the male of the latter — is that in 

 this species the three terminal joints of the legs are more compressed 

 and the posterior border of the meropodites is armed with a single 

 spine. 



Sub-family Sesarminj:, Dana. 

 Sesarma, Say. 



Sesarma, Say, Journ. Acad. Nat. Sci. Philad. I. 1817, p. 76 : Milne Edwards, 

 Hist. Nat. Crust. II. 71, and Ann. Sci. Nat. Zool. (3) XX. 1853, p. 181 : A. Milne 

 Edwards, Nouv. Archiv. da Ins. IX. 1873, p. 301 : Kingsley, Proc. Ac. Nat. Sci. 

 Philad. 1880, p. 213 : Miers, Challenger Brachyura, p. 269 : de Man, Zool. Jahrb., 

 Syst., II. 1886-87, p. 641 and IX. 1895-97, p. 128 : Burger, Zool. Jahrb., Syst., VII, 

 1S93-94, p 613. 



Pachysoma, De Haan, Faun. Japon. Crust., p. 33. 



Holometopus, Milne Edwards, Ann. Sci. Nat. Zool. (3) XX. 1853, p. 187. 



Carapace squarish or actually square (the sides being straight and 

 usually nearly parallel), usually deep (though occasionally shallow and 

 much depressed), seldom very convex: the gastric region is almost 

 always very well delimited, and is commonly divided into 5 subregions, 

 and in most cases the 4 antero-lateral subregions project as 4 prominent 

 post-frontal tubercles. 



The side-walls of the carapace have everywhere a characteristic fine- 

 meshed reticulate texture as regular as that of a sieve. This appearance 

 is due to a multitude of small uniform granules arranged in pairs in 

 close-set parallel rows : between each pair of granules is a little row of 

 bristles, one of which in each row is long and points diagonally forwards. 



The front occupies half, or more, of the anterior border of the 

 carapace, and is obliquely or vertically deflexed. 



