232 BULLETIN d1, UNITED STATES NATIONAL MUSEUM. 



Grapsus. Between the coxae of the second and third pairs of legs 

 is a narrow fossa fringed with hair leading to the branchial cavity. 

 Inhabits tropical America as well as the Oriental region. 



GEOGRAPSUS LIVIDUS (Milne Edwards). 



Plate 55. 



(irapsus lividus Milne Edwards, Hist. Nat. Crust., vol. 2, 1837, p. 85 (type- 

 locality, Antilles; type in Paris Mus.). — Dana, U. S. Expl. Exped., 

 vol. is', Crust., pt. 1, 1852, p. 340 ; atlas, 1855, pi. 21, figs. 5 a^. 



Grapsus hrevipc-^ Mu.yK Edwakus, Ann. Sci. Nat., ser. 3, Zool., vol. 20, 1853, 

 p. 170 [136], (Patrie inconnue; type in Paris Mus.). 



Geograpsus lividus Stimpson, Ann. Lye. Nat. Hist. New York, vol. 7, 1860, 

 p. 230. 



Geoyrapsiis occidcntalis Stimvson, Ann. Lye. Nat. Hist. New York, vol. 7, 

 1860, p. 230 (type-locality, Cape St. Lucas; cotypes in Mus. Comp. 

 Zool.). 



Orthograpsus hillii Kingsley, Proc. Acad. Nat. Sci. Philadelphia, 1880, 

 p. 194 (type-localities. West Indies; type in Mus. Phila. Acad. Sci., 

 and Key West, Fl;i.). 



Diagnosis. — Lateral margin well defined throughout its extent. 

 Front little deflexed. Fingers pointed. 



Description. — Carapace subquadrilateral, widening behind, a little 

 convex, lateral borders well defined, and posteriorly continued on the 

 dorsal surface nearly to its middle by, a sinuous line near the pos- 

 terior, border. Transverse markings fine, obsolescent on the gastric 

 region, absent on the cardiac region. 



The four tubercles along the upper border of the front are rather 

 prominent; edge of front in dorsal view nearly straight or slightly 

 concave at the middle. Notch near outer end of lower border of 

 orbit deep. 



Chelipeds in both sexes a little unequal; about one and one-half 

 times length of carapace, covered with transverse, more or less 

 squamiform striae; upper surface of last three joints tuberculous; 

 inner margin of arm expanded, proximally denticulate, distally with 

 larger teeth ; an acute tooth or spine at inner angle of wrist. 



The greatest breadth of the merus joints of the legs is more than 

 half their length. First pair of legs slightly shorter than the fourth, 

 second pair longest, two and one-third times as long as carapace. 

 Last three joints of all the legs conspicuous with long slender 

 bristles. 



6^o7(9?'.— Yellowish red with reticulating lines or patches of a 

 darker red or purplish ; sometimes wholly red. 



Measurements. — Male (24041). length of carapace 24.8, width of 

 same 30.2 mm. 



Tlahits. — Lives among loose stones and rocks along shore above 

 the water's edge. Probably nocturnal. 



