328 



28 



The largest specimen is the male from Koh Kong, which is 52 mm. long and 

 64 mm. wide. There is a faint second tooth on the lateral margin behind the 

 large tooth. The chelæ are unequal, hut the right or smaller one is abnormal in 

 shape and perhaps in size also. The prehensile teeth are uneven; in the larger 

 chela, the largest tooth is at the middle of the pollex; a smaller, but enlarged 

 tooth is on each finger next to the terminal spoon, much as in de Man's fig. 4 b; 

 in the smaller chela, which is a little constricted at the base of the pollex, there 

 is an additional large tooth at the middle of the dactylus. 



Sesarma (Sesarma) smithi Milne Edwards. 



Sesarma smiihi Milne Edwards, Arch. Mus. Hist. Nat., Paris, VII, 149, pi. IX, figs. 2, 2 a, 2 6, 2 e, 1854. 

 Sesarma siuithii A. Milne Edwards, Nouv. Arch. Mus. Hist. Nat., Paris, IX, 305, 1873. 



Mangrove swamp, Lem Ngob; XII. 23, 24 or 27; 1 c?- 



Compared with a specimen collected by M. Balansa at New Caledonia and 

 determined by A. Milne Edwards. 



Sesarma (Chiromantes) siamense Ralhbun. 



Sesarma ^Chiromantes) siamense Rathbun, Proc. Biol. Soc. W^ashington, XXII, 109, 1909. 



Carapace distinctly broader than long, widening a little posteriorly; lateral 



tooth slight, obtuse-angled; surface glabrous and coarsely punctate. Front half as 



wide as carapace; middle pair of upper lobes distinctly wider than outer pair; 



lower margin arcuate in front view, very faintly bilobed in dorsal view. 



Anterior margin of arm with 

 a slight obtusangular expansion; 

 inner angle of wrist blunt. Palm 

 higher than long, upper surface 

 marked by oblique striæ, two of 

 which are sharply marked, crenu- 

 late, while there are a few broken 

 striæ near the upper angle; 6 or 7 

 spinules on the upper edge of the 

 dactylus on its proximal two-thirds; 

 a few granules on inner surface of 

 palm; otherwise the chelæ are 

 smooth and punctate. When the 



chelipeds are folded naturally against the body, the oblique striæ of the palm are 



parallel to the front. 



The merus joints of the legs are armed anteriorly with a sharp, subdistal 



spine, last three joints sparsely furnished with long fine hairs. The legs of the 



third pair are little more than twice as long as carapace, their merus is about 



two and a half times as long as wide. 



Terminal segment of male abdomen very large, longer than, and more than 



half as wide as, the sixth segment. 



Fig. 11. Sesarma [Chiromanles] siamense, Koh Kong, c?, 

 8'7 mm. wide; a, chela; b, toi) of cliela; c. ahdomen. 



