16 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 descrzJ- 
tion: 
feostrum 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; @veo/a 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. 
Fpistoma 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; flagel//uwm shorter 
than carapace (but damaged at end). 
Chelipeds 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. 
Lschiopodite of third and fourth pereiopods with hooks, those 
of the third pereiopod are very small, but distinct and tubercu- 
