Opisthophthalmus in the British Museum. 243 



pilosus. In 0. Chaperi, for example, the humerus and 

 brachium of the chela are black, the interocular area is smooth 

 and punctured and only sparsely granular, and the hand is 

 flat and nearly smooth above. 



Opisthophthahnus nitidicevs, sp. n. 

 (PL X. figs. 2, 2 a.) 



? (in alcohol). — Colour. C.-irapace dark at the sides, pale 

 on the interocular area ; abdomen olive-brown, darker above 

 than below ; mandibles brown at the base, deep olive-green 

 distally ; chelas, legs, coxa?, and tail clear reddish yellow, the 

 fingers of the chelse and the crests on the hand being dark 

 brown. 



Carapace as long as wide, as long as the first two caudal 

 segments and half the third ; median eyes two thirds of the 

 length of the carapace from the anterior end ; interocular area 

 entirely smooth, sparsely punctured, the median sulcus deep 

 in front, but not bifurcating ; sides of the carapace weakly 

 granular, with no oblique ridge of granules running forward 

 from the median to the lateral eyes. 



Tergit.es smooth in the middle, finely granular at the sides, 

 the posterior edge rugose; the last granular throughout. 



Sterna smooth and polished, the last feebly granular. 



Tail with the lower surface of the first segment weakly 

 granular ; the inferior keels on all the segments distinct, but 

 not coarsely granular ; the superior keels on the second, third, 

 and fourth posteriorly strongly denticulate. 



Vesicle distinctly granular. 



Chelce large, humerus with its four crests strong and 

 granular, the front surface coarsely granular, the upper with 

 only a few large granules ; brachium with its upper crest 

 crenulate ; hand large, its upper surface convex and closely 

 covered with smooth, low, irregular-shaped, sometimes anasto- 

 mosing tubercles, its inner edge weakly denticulate, the 

 secondary keels obsolete, the finger-keel moderately large and 

 entire, the keel defining the hand-back above finely crenu- 

 late. 



Tarsi of third and fourth legs with two anterior spines in 

 addition to the four on the lobe ; lobes much longer than 

 upper process ; second protarsal segment of first three pairs 

 of legs externally spined, as in 0. opinatus. 



Genital operculum much wider than long. 



Pectines with long internal basal sclerite armed with 12 or 

 13 teeth. (PI. X. fig. 2 a.) 



