392 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



Large cheliped of male rather smooth. Merus with rugose lines on 

 upper and outer surfaces, and fine granules on lower half of inner 

 surface; edges of this surface tuberculo-denticulate. Wrist finely 

 granulate-rugose. Palm elongate, its outer aspect considerably nar- 

 rowed proximally on account of the palm being strongly bent over 

 to form a broad upper surface; outer upper surface granulate, gran- 

 ules varying in size, but on the whole coarser on the upper half. The 

 oblique ridge on the inner face which leads up to the carpal cavity 

 is broad and usually tuberculated, being several tubercles in width; 

 sometimes the tubercles are obsolete except at the proximal end. 

 Normally this ridge ends at the cavity but sometimes it is continued 

 upward by an angular turn. A more vertical ridge is situated on 

 the upper half and is continued in a curved line to the proximal end 

 of the upper margin. The two rows of tubercles at the base of the 



dactylus diverge from below upward 

 and leave a considerable space be- 

 tween them. Inner surface granulate, 

 granules coarser at the middle. Fin- 

 gers not much longer than palm, 



FIG. 166. UCA MORDAX, INNER SCR- B 



FACE OF LARGE CHELA OF MALE Wiafety gaping, dactylus longer than 



FROM PARA, SLIGHTLY REDUCED. po u ex an( J curving past it; polleX 

 (AFTER SMITH.) 



obliquely truncate at tip; surface 



almost smooth, shining, prehensile edges irregularly tuberculate, with 

 the largest tubercle at the middle of the pollex. 



Ambulatory legs hairy; merus joints enlarged (save in last pair) 

 and slightly rugose. 



The females are narrower than the males and the carapace is more 

 granulous. 



Measurements. Mule (21373), length 21.5, width 32.2 mm. 



Remarks. This species is extremely variable as to the ornamenta- 

 tion of the inside of the palm, but the characters of the carapace, 

 outside of the palm, etc., serve to distinguish it with certainty. 



Habitat. " Common in holes in the clay flat at the mouth of the 

 Manzanares River [Colombia] and at Punta Gruesa in holes in 

 sand, under logs, and among mangrove roots." (Pearse.) 



Range. From the Bahamas and Gulf of Mexico to Rio de Janeiro. 

 West coast of Mexico. Liberia ( ?). 



Material examined. 



Cameron, Louisiana; R. P. Cowles; 1 male (30570). 



Tampico, Mexico : Live in the soft mud of the river banks ; June 

 1, 1910; Edward Palmer; 8 males, 1 y. (43353). A. Duges; 1 male 

 (18689). 



Belize, British Honduras; Rev. W. A. Stanton; 11 males, 4 fe- 

 males (21373 and 22G04). 



