294 BULLETIN 97, UNITED STATES NATIONAL MUSF.UM, 



SESARMA (SESARMA) RHIZOPHORAE Rathbun. 

 MANGROVE CRAB. 



Plate 79. 



Sesarma (Sesarma) rliizoph<yrae Rathbun, Proc. Biol. Soc. WasliiiigtoQ, 

 vol. 19, 190G, p. 99 (type-locality, Boca del Jesus Maria, Costa Rica, 

 holotypo male. Cat. No. 32491, U.S.N.M.). 



Diagnosis. — Lateral tooth, acute. Middle pair of supra-frontal 

 lobes wider than outer pair. Legs slender. 



Description.— The Pacific representative of S. curacaoense. Cara- 

 pace and legs densely tomentose. The middle pair of post-frontal 

 lobes are more prominent and much wider than the obscure outer 

 pair. Lower margin of front less convex in front view. Lateral 

 tooth acute. The granules on the upper surface of the daetylus, 

 9 or 10 in number, are confined to the basal half. The legs are 

 longer and more slender, the third leg being two and one-fourtli 

 times as long as carapace, with its merus two and one-half times 

 as long as wide; spine on the merus long and slender; dactyli long 

 and slender. Abdomen of male narrower, the appendages of the 

 first segment ending in long needle-like points. 



Measurements. — Male type, length 10.9 mm., width 13.7 mm. 



Habitat. — In the mud of mangrove swamps. 



Locality. — Costa Rica ; Boca del Jesus Maria. 



Material examined. — Boca del Jesus Maria, Costa Rica : In man- 

 grove swamps; Apr., 1905; J. F. Tristan; 1 male (32318). On 

 mangroves in mud; Jan. 1906: J. F. Tristan and P. Biolley; 1 male 

 (32491). 



SESARMA (SESARMA) CRASSIPES Cano. 



Sesarma crassipes Cano, Boll. Soc. Nat. Napoli, ser. 1, vol. 3, 1899. pp. 93 

 and 244 (type-locality, Peinambuco; type in Naples Mus.). 



Diagnosis. — Rather narrow. Supra-frontal lobes equal. Side mar- 

 gins straight, tooth small. 



Description (condensed from Cano). — Of medium size. Cara- 

 pace rather nari-ow, its length 0.84 of its width. Surface rugulose 

 and pubescent. Mesogastric area well defined, epigastric and proto- 

 gastric lobes equally wide. 



Front deeply sinuous. Lateral margins almost straight. Tooth 

 at orbit acute and advanced, lateral tooth small and elevated above 

 the first; behind it, a rudiment of another to( tli. 



Surface of arm rugulose, inner margin denticulate, lower margin 

 armed with a tooth. Carpus granulous-squamose. Hand elongate, 

 scarcely rugose, a crenulated crest above. Daetylus toward the base 

 spinulous. 



Legs rather robust; merus broad, with a superior spine, surface 

 squamose and scarcely villose; three remaining joints villose. above 

 hirsute. 



