4 NEW-YORK FAUNA — CRUSTACEA. 
GENUS MITHRAX. Leach. 
Shield moderately convex above, longer than broad, and more or less narrowed behind, usually 
armed with spines. Rostrum short, bifid, and separated by an interval from the internal 
canthus. Orbits usually armed with spines above and beneath. External antenne not 
concealed by the rostrum. Pincers enlarged towards the end, rounded and spoon-shaped. 
Oxs. We have no type of this numerous genus on our coast, except the following, which 
is cited by Mr. Say from Delaware bay, and which we think will be found on the coast of 
this State. 
Mirurax HISPIDUS. 
Cancer hispidus. Hersst, pl. 18, fig. 100. 
Maia spinicincta. Lamarck, An. sans vert. Vol. 2, p. 415, Ed. Brux. 
Mithrax spinicinctus. Drs. Consid. sur les Crust. p. 150, pl. 23, fig. 1. 
Maia id. Say, Journ. Acad. Nat. Sc. Vol. 1, p. 458. 
Mithrax hispidus. Epwarps, Hist. Nat. des Crust. Vol. 1, p. 322. 
Description. Shield short, convex, with its surface and margin spinous. Rostrum not ex- 
tending beyond the basal joint of the external antenne, which are furnished with but two 
spines ; the third joint of these antenne considerably longer than the second. Upper border 
of the hands smooth. Pincers with about twenty indentations on the margin, but with no tuft 
of hairs in the cavity. A series of small points under the tarsus of the four posterior pairs of 
feet. 
This species, of which a specimen exists in the Cabinet of the Academy of Natural Sciences 
at Philadelphia, from Delaware bay, extends through the Caribbean sea to the coast of Brazil. 
Its northernmost geographical range is not yet ascertained. 
(EXTRA-LIMITAL.) 
Genus XantuHo, Leach. Exterior antenne very short, inserted at the internal canthus of the eyes. 
Hands trenchant or rounded. A hiatus below the external orbital angle. Shield wider than 
long, arcuated in front, truncated behind, 
X, mercenaria. (L. id. Say, Jour. Acad. Nat, Sc. Vol. 1, p. 448. Epwarps, l.c. p. 899.) The 
anterior lateral borders of the shield with four obtuse teeth; front with a slightly sinuous fissure. 
Feet hairy. Color, maculated; fingers black at tip. Length, 3°25; diameter, 4°5, Charles- 
ton, S. C. 
