228 BULLETIN 97, UNITED STATES NATIONAL MUSEUM. 



Diagnosis. — Front vertical. Tootli on wrist with short, spini- 

 form tip. P'ingers spoon-shaped. 



Description. — Carapace discoidal; transverse and oblique ridges 

 prominent, intervening spaces reticulate. Front deep (depth vari- 

 able), almost vertical, overhanging the ejnstome, partly concealing 

 the antennules, its free edge crenate. 



Length of epistome about one-third its greatest breadth. Tooth at 

 inner angle of orbit subovate. 



Chelipeds in male about as long as carapace, shorter in the 

 female; inner border of ischium and arm strongly spinate; distal 

 half of outer border of arm less deeply spined; wrist with scat- 

 tered tubercles on its upper surface and with its inner angle pro- 

 duced in an ovate, falcate tooth with a short spiniform tip; palm 

 nearly as high as long, its outer surface sculptured, its upper 

 border culminating in a tooth; fingers with very broad rounded 

 tips ; length of dactylus in male nearly twice the length of the upper 

 border of the palm. 



First pair of legs shortest, fourth pair next, 

 third pair longest, about twice as long as cara- 

 pace. Only in the last pair of legs does the 

 breadth of the merus approach half its length ; the 

 distal end of the upper border of each merus is a 

 FiQ. 135.— Grapsus spine, while the same end of the lower border in the 

 GRAPsus, OUTER g^^^ thrcc palrs is armed with two or three spines. 



MAXILLIPED, EN- i ^ 



LARGED. (After Measurements. — Male (16032), length of cara- 



MiLNE Edwards.) ^^^^^ ^^^ ^^^^.j^ ^f ^^^^ g^ ^^ 



Color. — Usually variegated with deep red and light greenish (in 

 alcohol). Chelae an even, brilliant red. Sometimes the carapace 

 and legs are entirely red without mottlings. 



Hahits. — According to Catesby, " these crabs inhabit the rocks 

 overhanging the sea; they are the nimblest of all other crabs; they 

 run with surprising agility along the upright side of a rock and even 

 under rocks that hang horizontally over the sea ; this they are often 

 necessitated to do for escaping the assaults of rapacious birds which 

 pursue them. These crabs, so far as I could observe, never go to 

 land, but frequent mostly those parts of the promontories and islands 

 of rocks in and near the sea, where by the continual and violent 

 agitation of the waves against the rocks they are always wet, con- 

 tinually receiving the spray of the sea, which often washes them into 

 it, but they instantly return to the rock again, not being able to live 

 under water and yet requiring more of that element than any of 

 the crustaceous kinds that are not fish." 



Range. — Tropical and subtropical shores of America as well as 

 of the eastern Atlantic. South Florida and Bahamas to Pernambuco. 

 Brazil; Bermudas; Lower California (San Benito Island) to Chile. 



