GRAPSOIDEA. 357 



Carapax stout, very slightly areolate, quadrate, anteriorly very slightly 

 narrower than near middle, the sides almost arcuate, in no part 

 with an acute edge, antero-lateral margin entire, front perpen- 

 dicular, line above nearly straight, margin below regularly arcuate. 

 Epistome granulate. Anterior feet short, hand short, not granulous, 

 above entire and short. Eight posterior feet narrow, fourth joint 

 not hirsute above, fifth with some very short hirsute tufts, tarsus 

 very short hirsute. 



Plate 22, fig. 10a, male, natural size; b, male abdomen and sternum, 

 enlarged two diameters ; c, hand, natural size. 



Straits of Balabac. 



Length of carapax, six lines ; breadth, six and three-fourths lines. 

 Body thicker than usual, and peculiar in having no acute margin, but 

 rounded sides, except close to the anterior angles. The front is ver- 

 tical, and the vertical surface flat ; the margin above is nearly straight, 

 the usual prominences being but slightly indicated. 



S. obesum, Dana, Proc. Acad. Nat. Sci. Philad., 1851, v. 250. 



Genus SAKMATIUM, Dana. 



Carapax longitudinaliter convexus, fronte sat brew (latitudine carapacis 

 duplo breviore), curvatim declivi, later ibus arcuatis. Articulus maxil- 

 Ivpedis externi Otitis subellvpticus, apice rotundatus, 2do vix brevior. 

 Abdomen maris 7-articidatum, articulo 2do sternum posticum usque 

 ad latera vix omnino tegente. 



Carapax longitudinally convex, front short, curvately inclined, sides 

 arcuate. Third joint of outer maxillipeds subelliptical, rounded at 

 apex. Second joint of male abdomen not covering the correspond- 

 ing parts of the sternum quite to its sides. 



Like Sesarma, this genus has the third joint of the outer maxilli- 

 peds rounded above. But Sesarma has a vertical front much longer 

 than half the breadth of the carapax, besides straight sides, and an 



90 



