THE GEAPSOID CRABS OF AMERICA. 227 



is filled partly by the antennal peduncle and partly by a strong iso- 

 lated tooth in the inner fossa. 



Antennules nearly transverse in narrow fossae; interantennular 

 septum very broad. Antennal flagellum short, lying in the orbital 

 hiatus; excretory tubercle of basal joint very prominent. 



Epistome deep, from front to back, well defined, its wings run up 

 toward the orbital hiatus. Buccal cavity square with the antero- 

 lateral corners rounded off. External maxillipeds widely separated 

 by a rhomboidal gap in which the mandibles are exposed; ischium 

 and merus narrow, the latter slightly the shorter; and the palp, 

 which is coarse, especially as to its carpus, articulates near the antero- 

 external angle of the merus. 



Chelipeds subequal, much shorter than the legs, but in the male 

 much stouter; hands and fingers short and stout, tips of fingers broad 

 and hollowed in a spoon. 



Legs broad and compressed, especially the merus; dorsal surface 

 of some of the joints has a striated or squamiform sculpture; dactyli 

 thorny. 



Abdomen with seven segments in both sexes; in the male its base 

 is as broad as the sternum between the last pair of legs. 



Found on rocks and reefs of all tropical and subtropical seas. 



GRAPSUS GRAPSUS (Linnaeus). 



ROCK CRAB ; SALLY LIGHTFOOT. 



Plates 53 and 54. 



Paffurus maculatus CATESBY, Nat. Hist. Carolina, Florida, and the Bahama 



Islands, vol. 2, 1743, p. 36, pi. 36, fig. 1, " inhabit the rocks overhanging 



the sea." 



Cancer grapsus LINNAEUS, Sys. Nat., ed. 10, vol. 1, 1758, p. 630 (type-locali- 

 ties, America and Ascension Island; types not extant). 

 Grapsus pictus LATREILLE, Hist. Nat. Crust., vol. 6, an XI 11802-1803], 



p. 69 (type-locality, les ties de VAmtrique m^ridionale ; type in Paris 



Mus.). 

 Grapsus webbi MILNE EDWARDS, Ann. Sci. Nat., ser. 3, Zool., vol. 20, 1853, 



p. 16. 



Grapsus (Goniopsis) pictus DE HAAN, Fauna Japon., Crust., 1835, p. 33. 

 Grapsus maculatus MILNE EDWARDS, Ann. Sci. Nat., ser. 3, Zool., vol. 20, 



1853, p. 167 [133], pi. 6, figs. 11 n (type-locality, Antilles; type in 



Paris Mus.). 

 Grapsus webbi MILNE EDWARDS, Ann. Sci. Nat., ser. 3, Zool., vol. 20, 1853, 



p. 167 [133] (type-locality, Canary Islands; type in Paris Mus.). 

 Grapsus ornatus MILNE EDWARDS, Ann. Sci. Nat., ser. 3, Zool., vol. 20, 



1853, p. 168 [134] (type-locality, Chili; type in Paris Mus.). 

 Grapsus altifrons STIMPSON, Ann. Lye. Nat. Hist. New York, vol. 7. 1860, 



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



and Cat. No. 2022, U.S.N.M.). 

 Grapsus (jrapsus IVES, Proc. Acad. Nat. Sci. Philadelphia, 1891. p. 19O. 



