1 6 ORTMANN 



Lake Xochimilco, south of City of Mexico (Federal District). 

 — E. D. Cope coll., 1885. 



This male has enabled me to draw up the following descrip- 

 tion : 



Rostrum broad, moderately long, plane above ; margins ele- 

 vated, slightly convergent anteriorly, near the tip more strongly 

 convergent, and forming a short, subtriangular acumen ; no 

 marginal spines nor marginal angles at base of acumen, and 

 the elevated margins continued to the tip, which is bluntly 

 pointed ; postorbital ridges divergent posteriorly, without spines 

 anteriorly ; carapace ovate, slightly compressed, punctate, 

 slightly granulated on the sides ; suborbital angle blunt, branchi- 

 ostegal spine distinct, but blunt (tuberculiform) ; cervical groove 

 sinuate ; no lateral spine ; areola longer than half of the anterior 

 section of carapace, rather narrow in the middle, with two to 

 three irregular rows of punctations. 



Abdomen as wide as, and slightly longer than, the carapace ; 

 anterior segment of telson with three spines on each side ; pos- 

 terior segment semicircular. 



Ejyistoma with anterior part almost semicircular, a little an- 

 gular on the sides, and bluntly pointed at the middle ; antennal 

 scale broad, broadest anterior to the middle ; jlagellum shorter 

 than carapace (but damaged at end). 



Chclipeds with hand rather wide, not much swollen, com- 

 pressed, with subparallel margins ; surface squamoso-tubercu- 

 late, tubercles on inner margin more crowded and stronger, 

 forming an irregular row of serrations ; fingers strong, about as 

 long as the palm, with longitudinal ribs and punctations on outer 

 face, and with squamiform tubercles at the bases ; cutting edges 

 tuberculated, tubercles irregular, a larger one near the base of 

 each finger, and another large one near the distal end of immov- 

 able finger ; carpopodite squamoso-tuberculate, inner side with 

 several spiniform tubercles, upper surface with a slight longi- 

 tudinal sulcus; meropodite smooth, with a few tubercles near 

 distal end of upper margin, and two rows of tubercles on lower 

 margins, the outer ones shorter. 



Ischiofodite of third and fourth pereiopods with hooks, those 

 of the third pereiopod are very small, but distinct and tubercu- 



