DECAPOD CRUSTACEANS OF THE WEST INDIES 123 



occurs in larger numbers than below, and yet higher, Geograpsus is 

 the dominant crab. Both of the latter invade the zone inhabited by 

 Petrolisthes, but the porcellanid does not wander so far from the 

 water as does Cyclograpsus, and the latter not so high as does 

 Geograpsiis. 



Distribution. — Puerto Rico, Dominica, Isla Cubagua, Curagao, 

 Aruba, Panama. 



Dominica Station: 110. 



Remarks. — The holotype of Petrolisthes quadratus, figured by 

 Benedict (1901), is a female; in that sex, the chelipeds differ from 

 those of the male in having the carpus marked by slightly rugose 

 ridges and the chela less swollen, with sharper fingers. The detached 

 walking legs associated with the holotype are very different from those 

 of all other specimens subsequently assigned to the species; it seems 

 unlikely that they belong to the type-specimen. 



All of the Dominican specimens of P. quadratus were collected 

 on February 27. 



Family Coenobitidae 

 Genus Coenobita 



35. Coenobita clypeatus (Herbst) 



Figures 33, 346, c 



Cancer clypeatus Herbst, 1791, p. 22, pi. 23: figs. 2a— b [type-locality: "East Indies" 

 (Hilgendorf, 1869, p. 98, noted that Herbst's type specimen — at that time in 

 the Berlin Museum but probably subsequently destroyed — belonged to the 

 West Indian species then called Coenobita diogenes)]. 



Pagurus Diogenes. — Latreille, 1818, p. 2, pi. 284: figs. 2, 3 [not Cancer diogenes 

 Linnaeus, 1758]. 



Cenobita Diogenes. — H. Milne Edwards, 1837, p. 240. 



Cenobita diogenes.— Pocock, 1889, p. 6.— Verrill, 1892, p. 353. 



Coenobita clypeatus. — Rathbun, 1920, p. 329. — Provenzano, 1959, p. 359, fig. 3; 

 1962, p. 207, figs. 1-12. 



Diagnosis. — Eyestalks flattened on mesial surface. Antennular 

 peduncle five times as long as eyestalks, flagellum blunt tipped. An- 

 tennal peduncle originating below eyestalk, Chelipeds unequal, left 

 much larger than right, studded with closely appressed, dark-tipped 

 spines. Tliird left pereiopod (second walldng leg) with propodus and 

 dactyl very broad, flattened, and smooth, with flexor margins rather 

 sharp and obscurely serrate. Hermit crab usually occupying gastropod 

 shells. A medium-sized to large species, maximum carapace length in 

 midline at least 50 mm. 



Color in life. — Carapace mauve dorsally, white dorsolaterally, 

 lavender laterally, and white anteroventrally and ventrally. Tliree 

 leathery terga of abdomen white with transverse ridges between terga 



317-180—69 10 



