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U.S. NATIONAL MUSEUM BULLETIN 292 



slightly wider than eyestalk. Ventral margin of orbit sharply pro- 

 duced, obscurely denticulate in median portion, rather regularly 

 arched between suborbital notch and anterolateral angle of mouth 

 area. Third maxillipeds without oblique hairy ridge, widely gaping, 

 exposing mandibles. Chelipeds subequal, carpus armed with broad 

 flattened sharp-tipped spine on flexor margin; palm with few rounded 

 dorsal tubercles; fingers rounded and distinctly spooned distally, 

 extensor margin of movable finger bearing few large sharp tubercles. 

 Walkmg legs moderately broad and flattened, merus of third pereiopod 

 less than half as wide as long, with promment acute subdistal tooth 

 on extensor margin; dactyl slightly more than three-fourths as long 



Figure 50.— Grapsus grapsus, male (carapace length 44.0 mm) from Dominica station 114. 



as extensor margin of propodus. Denuded first pleopod of male 

 terminating, in posterior view, in rather long slender chitmous dis- 

 tally notched endpiece directed anteriorly and slightly laterally 

 (fig. 52g) . Color pattern of adults characterized by numerous irregular 

 light spots and splotches on darker background. A large species, 

 maximum carapace length in midline about 77 mm. 



Color in life. — Ground color of carapace maroon brown to black 

 vnih pale blue markings (in young crabs, dark chromatophores not 

 overlapping to extent in larger animals, thus more blue). Orbits 

 pale blue. Except for urogastric, cardiac, and intestinal areas, pattern 

 of light blue spots and bands extending across carapace in posteriorly 

 convex arcs; although less well defined in gastric regions, similar 

 arrangement of spots present posteriorly. Posterior portion of proto- 

 gastric region with larger blue areas than elsewhere, and in some 



