PACHYCHELES PANAMENSIS. 71 



PACHYCHELES Stimps. 



Proc. Acad. Nat. Sci. Phila., X. 22S, 1858. 



Pachycheles panamensis Fax. 

 Plate XV., Fig. 2, 2\ 



Bull. Mus. Comp. Zool., XXIV. 175, 1893. 



Carapace subcircular, the longitudinal and transverse diameters nearly 

 equal, upper surface flattened, granulate and setose, especially on the gastric 

 and anterior portion of the branchial regions, posterior portions of the 

 branchial regions lightly rugose. Front broad, produced to a rounded 

 median lobe, lateral portions straight, inner orbital angle rounded, not pro- 

 duced ; outer orbital angle projecting as a triangular tooth between the ej-e 

 and the base of the antenna. Lateral border of the carapace with a con- 

 cavity behind the antenna ; the margin is slightly raised as a rim which is 

 lost in one of the branchial rugai before reaching the liind border of the cara- 

 pace ; hind border slightly concave. Chelipeds imequal, the riglit being 

 the larger ; upper surface of the merus rugose and setose, wider surface 

 smooth, internal distal angle produced as a denticulated tooth ; carpus short 

 and broad, upper surf;\ce tuberculous and setose, internal border armed with 

 a large tooth at the base, followed by one or two smaller teeth, lower surface 

 smooth and nalvcd ; upper surface of the propodite furnished with small 

 tubercles which bear stiff bristles, inner margin rounded, not toothed, outer 

 margin granulated, lower suface convex, naked and polished near the centre 

 (where the surface is reticulated in the larger claw), squamoso-granular and 

 setose near the edges ; fingers gaping, crossing at tips, toothless on both the 

 inner and outer margins (or at most slightlj^ denticulated on the outer mar- 

 gin). Ambulatory appendages setose. 



Length of carapace, 6.5 mm., breadth, 7 mm.; breadth of frontal margin, 

 2 mm. 



Panama, March 12. 1 fem. ovig. 



Pachjchdcs rudis Stimps. is a larger species, with the posterior margin of 

 the carapace more concave (the concavity' having almost the shape of a trian- 

 gular notch) ; the carapace and chelipeds are less setose than in P. panamensis, 

 the anterior margin of the carpus not prominently toothed, and there is a 

 strong protuberance near the middle of the upper surface of the propodite. 

 In P. tuberculipes Lockington the central part of the front is triangular and 



