280 



BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



U sinus; outer orbital tooth strong, sharp and curved slightly inward. 

 The first three teeth of lateral margin elevated, acute, the second 

 the smallest, the third very prominent; last tooth very small, acute. 

 Margins behind that tooth subparallel. Lower margin of orbit 

 oblique, crenulate; outer sinus very broad and deep; inner tooth 

 large, spinulous on the outer margin. Infero-lateral regions densely 

 hairy. 



Chelipeds strikingly unequal in length and thickness. The mar- 

 gins of the chelipeds and legs are spinulous, and their surfaces are 

 more or less tuberculous. The inner margin of the upper surface of 

 the wrist is rounded, but below the angle there are a few spinules on 



FlO. 143. — PLATTCHIROGBAPSDS TYPICDS, UIGHT OB MAJOR CHELIPED. a, ANTEmOK VIEW 



OP si-EciMEN IN Halifax Mdseum, natuual size; h, uppeu view of same, natuual 



SIZE ; C, ANTEBIOa VIEW OF 198G3, X li. 



the inner surface. The propodus of the large chela is enormously 

 developed, being expanded proximally in a projection which may 

 equal in length the distance from the superior articulation with the 

 carpus to the dactylus; outer face quite flat, three times as long as 

 high, widening distally, covered with tubercles; upper surface flat, 

 at right angles to the outer, narrowing a little distally. Fingers 

 short and thick, pollex triangular, dactylus of nearly equal width 

 throughout, slightly excavate at base of prehensile edge. Edges of 

 both fingers set with low teeth and hollowed in shallow grooves. 

 Smaller chela normal, palm widening distally, not much longer than 

 the fingers measured horizontally. 



The supero-distal spine on the merus of the legs is strong and acute, 

 and most recurved on the first leg. Legs sparingly hairy; a short 

 fur on the margins of the last three joints of the last pair. Dactylus 



