122 
CRUSTACEA. 
and bearing the palpus on the inner side of the ex- 
ternal angle ; the arrangement is such that when 
the maxillary feet are brought together, the apices 
diverge, leaving between them a nearly semi-cir- 
cular excavation ; epistoma broad, and nearly on a 
line with the floor of the orbits ; tail broad in the 
males, but extremely so in the females. 
0. dentata. Mus. Acad. 
Testa gramilata,margine utrinque 10-dentata; fronte mul- 
tidentata, obtuse bilobata. 
Orbits of the eyes dentate inferiorly ; regions of 
the carapax not very strongly defined, antero-lateral 
margin with ten teeth on each side ; front greatly 
depressed, but not vertical, obtusely bilobate, and 
armed with fifteen or more small but sharp teeth ; 
anterior feet moderately elongate; arm with one 
strong tooth on the under side; carpus slightly 
roughened, one strong tooth on its anterior inner 
side; hands unequal in both sexes, but especially 
so in the male, the right being largest ; pincers ca- 
rinate, large, and irregularly toothed, the large 
tooth being separated by several smaller ones ; four 
posterior pairs of feet somewhat flattened; tarsi 
much flattened, and carinate both on their superior 
edge and laterally. Color reddish. 
Length, as measured in four specimens, from 
lj inches to 2 inches. 
Supposed to have been brought either from South 
America or the West Indies. 
This species has, at first sight, much resemblance to 
the Cancers, owing to the breadth of its lateral crest. 
