FRESH-WATER CRABS OF AMERICA— RATHBUN. 



517 



Dimensions. — Male: Length, 16 mm,; width, 27.5mm.; exorbital width, 

 17.5 mm. Female: Length, 18.7 mm. ; width, 33.5 mm. ; exorbital width, 

 20 mm. 



Types. — No. 19486, U.S.N.M.; two males and two females; Costa Rica: 

 La Palma, 1,500 meters, under trunks of trees; J. Fid Tristan, Febru- 

 ary, 1896. 



PSEUDOTHELPHUSA TUMIMANUS, new species. 



Superior margin of front smooth, not heeled; ambulatory leys rvide; 

 mantis ivith a tubercle at base of fingers. 



Allied to r. tristani, but a much larger species. Carapace smooth, 

 densely punctate. Cervical suture wide and nearly transverse in its 

 inner lialf, then narrowing and curving abruptly forward, becoming 

 obsolete near the margin of the carapa(;e. Median furrow deep, cross- 

 ing the upper frontal margin. Ei)igastric 

 lobes marked by deep grooves. Lateral mar- 

 gin of carapace obscurely denticulate; in tlie 

 largest specimen without additional teeth ; in 

 the three smaller specimens one or two teeth 

 are faintly indicated. Front (fig. 7, a) with a 

 marginate rim on its lower and lateral bor- 

 ders; lower border sinuous; front deepest near 

 the middle. Orbits similar in shape to those 

 of tristani, but wider; eyes much smaller than 

 the orbits. Appendages of first abdominal 

 segment of the male (fig. 7, e, f) resembling 

 those of montowa, but the subterrainal lobe on 

 the outer side is less thickened, and the pos- 

 terior lobe less angular, than in that species. 

 The maxillipeds (fig, 7, c) differ slightly from 

 those of tristani; the meri are broader; their 

 inner edges, instead of being marginate and subparallel, as in that spe- 

 cies, are flat, and divergent anteriorly; the outer margins are more 

 oblique than in triiitani. 



The chelipeds of the male are heavy and unequal. The teeth on the 

 anterior or inner margin of the nierus are very large and blunt, increas- 

 ing in size distally. Propodus similar in shape to that of tristani, but 

 inferior njargin more convex, the greatest width of the segment being 

 near the digital end of the palm. Fingers thick, slightly gaping, sur- 

 face mottled with Hattened black granules, scarcely perceptible to the 

 touch ; teeth black. There is a large round smooth wart or protuber- 

 ance on the manus between the digits and in line with the teeth of 

 their cutting edges (fig. 7, b). 



Dimensions. — Male: Length, 42.2 mm.; width, 70.2 mm.; width of 

 front (lower margin), 18 mm.; greatest depth of front, 3 mm. 



JHstribution.— This is a Costa Ri(;an species taken in considerable 

 numbers at Cachi, Iteventazou Kiver, 1,300 meters, by Mr. J. Fid Tris- 



FlG. 7.— PSEDDOTHELPHnSA TD- 

 MIMANUS, MALE. a. KBONT X J. 



h. Lauoekchkla, X §. c. Max- 

 iLLii'Ei), x f;. d. Ahdomen, x §. 



e. Left abdominal APPENDAGE, 



LOWER VIEW, X J J. /. The 



SAME, INNER VIEW, X IJ. 



