THE SPIDER CBABS OF AMERICA 



311 



E^. Fork of rostrum in young deeper than in dubia, horns acute, curved 

 toward each other. Lateral marginal spines in young small 

 except the posterior one which is very long and slender. 



erinacea, p. 321. 

 D^ A spine at middle of hepatic region. 



E'. Carapace with a lateral marginal arc of 5 spines. Lower fissure of 

 orbit closed. 

 F'. A rhomb of 4 spines on branchial region besides the marginal 

 arc. Orbit deep, projecting well beyond outline of carapace. 



rhomboidea, p. 323. 

 F^. Five spines on branchial region besides the marginal arc. Orbit 

 shallow, not projecting beyond outline of carapace. 



ferreirae, p. 324. 

 E^. Branchial region (in the young) with only 3 spines, all long, 1 mar- 

 ginal, 2 dorsal. An open sinus below orbit mexicana, p. 328. 



B^. Rostrum ascending, hollowed beneatli, forming with the antennae an 

 efferent channel. Median tubercles q;- spines 8; a rhomb of 4 on bran- 

 chial region; no lateral marginal arc of spines setosa, p. 327. 



A*. Merus of chelipeds armed witli longitudinal rows of tubercles and spines. 

 Horns widespread and half as long as rostrum rostrata, p. 329. 



Lihinia'^. verrucosa Lockington from Mazatlan^^ is a nomen nudum. 

 Species reported on both sides of the continent: emarginata, 

 spinosa, rostrata. 



LIBINIA EMARGINATA Leach 



COMMON SPIDER CRAB 

 Plates 110-113 



Libinia emarginata Leach, Zool. Misc., vol. 2, 

 1815, p. 130, pi. 108 (type-locality unknown; 

 type in Brit. Mus.). — Rathbun, Proc. U. S. 

 Nat. Mus., vol. 15, 1892, p. 235, pi. 31, fig. 

 2, and synonymy. — Hay and Shore, Bull. 

 Bur. Fisheries, vol. 35, 1915-16 (1918), p. 

 456, pi. 38, fig. 6, and synonymy. 



Libinia canaliculata Say, Journ. Acad. Nat. 

 Sci. Philadelphia, vol. 1, 1817, p. 77, pi. 4, 

 fig. 1 (type-locality, bays and inlets of the 

 [east] coast; cotypes from Great Egg Har- 

 bor, in Mus. Phila. Acad. Nat. Sci.; speci- 

 mens, probably cotypes, in Brit. Mus., 

 "presented by T. Say").^' 



Libinia affinis Randall, Journ. Acad. Nat. 

 Sci. Philadelphia, vol. 8, 1839, p. 106 (type- 

 locality. Upper California; two small male 

 types, labeled "NW coast America," are in Mus. Phila. Acad. Nat. Sci.). 



Diagnosis. — Carapace with nine median spines or tubercles. 

 Dorsal tubercles many. No spine at angle of buccal cavity. 



Description. — Surface of body and limbs densely pubescent. Cara- 

 pace, without rostrum, nearly hemispherical in the old, narrower 

 anteriorly in the young; regions well marked; covered with short 

 spines and tubercles. Median spines 9, of which 4 are gastric, 1 

 genital, 2 cardiac, and 2 intestinal. Lateral marginal spines 5 on each 



Fig. 103.— Libinia emarginata 

 (3898), maxili.iped, x 2.85 



" Proc. California Acad. Sci., vol. 7, 1876 (1877), p. 64. " White, List Crust. Brit. Mus., 1847, p. 4. 



