334 



34 



Kig. 16. Pinnotheres nigrans, type 9, 

 8'3 inm. wide. 



Pinnotheres nigrans Rathbun. 



Pinnotheres nigrans Rathbun, Proc. Biol. Soc. Washington, XXII, 110, 1909. 



A species allied to P. lafiis Bürger', in 

 which the dactylus of the endognath is styli- 

 form, inserted on the inner margin of the pro- 

 podus, the dactyli of the third and fourth legs 

 are longer than those of the first and second 

 legs, the third leg not much longer than the 

 others, and the carapace considerably broader 

 than long and somewhat six-sided. Our species 

 differs from P. latus chiefly in the form of the 

 maxilliped, the dactylus not reaching the end 

 of the propodus, and the latter tapering toward 

 the end. 



Female. — Carapace about one-fifth broader 

 than long, very high in the middle and sloping down on all 

 sides, regions partially indicated by pits and grooves, anterior 

 margin advanced at the middle. Orbits not visible in dorsal 

 view, and with the antennæ occupying about two-sevenths of 

 the width of the carapace; orbits small, transversely oblong, 

 corneæ black, subterminal. 



Cheliped (the right only is present) not much stouter than 

 the legs, wrist elongate, palm widest at distal end, margins 

 almost straight, IS times as long as the fingers, but not so 

 high as the lengtli of the fingers, which cross at the tips and 

 do not gape. 



Legs not varying much in length, third longest, second 

 and fourth subequal, first shortest; dactyli of third and fourth pairs longest, equal, 

 twice as long as those of the first and second pairs. 



Dimensions. — Female, length 68 mm., width 83 mm. 

 Color. — Dark in alcohol, caused by numerous minute dots which in some 

 places are densely crowded, especially toward the antero-lateral angles. 



Type locality. — Koh Lan (west of Koh Chang); III. 9; 1 ? ovig. 



Among the male Pinnotlierids are three different forms which I am not able 

 to refer to the foregoing species. All are of minute size and have the front well 

 advanced and the eyes very large (for the genus). As, in some species where both 

 sexes are known, the fronto-orbital region is of much more importance in the male 

 than in the female, and tlie size of the crab is less in the male, it seems probable 

 that the males under discussion belong to the genus Pinnotheres, and it is possible 

 that examination of more material would indicate that one or more of these male 



Fig. 17. Maxilliped of 



Pinnotheres nigrans, 



type 9. S-.S mm. wide. 



' Zool. Jahrb., Syst., VIII, p. 363, 374, pi. IX. lig. 16, pi. X, lig. 15, 1895. 



