130 SMITHSONIAN MISCELLANEOUS COLLECTIONS 



angle of the orbit. The external suborbital lobe is obsolete. Infra- 

 orbital crest inconspicuously crenulated. In the outer maxillipeds 

 the exognath is always smooth ; the endognath sometimes pubescent. 

 Chelipeds large, smooth ; meros with ciliated margins ; carpus obtuse 

 within ; hand broad, little convex, smooth within ; fingers somewhat 

 gaping, denticulated within. Ambulatory feet sparsely hairy, to- 

 mentose toward their extremities ; dactyli robust, sulcated. Color 

 dark yellowish brown, often covered with a blackish incrustation. 

 Dimensions of a male: Length of carapax, 0.56; breadth, 0.68 inch. 

 This species lives in holes in gravelly mud, along the shores of 

 ponds of brackish water, at the mouths of streams. Found in Port 

 Lloyd, Bonin Island. 



Genus ACM.^OPLEURA Stimpson 



In the characters of the orbits, antennae, abdomen, etc., this genus 

 agrees with Cyclograpsus — at least with that section of it in which 

 the orbits are nearly complete below. The lateral margins of the 

 carapax are entire. The outer maxillipeds, however, nearly re- 

 semble those of Heterograpsus, being destitute of an oblique pilifer- 

 ous crest ; their sides are straight ; the meros-joint is square, equal- 

 ing the ischium in length, and marked on its surface with a some- 

 what oblique sulcus which is not continued on to the ischium ; the 

 palpus is prosarthroid, and finally the exognath is narrow. The 

 hands are lanose at or between the bases of the fingers. 



This genus, being founded upon a single small specimen, needs 

 further illustration. The characters above mentioned forbid its 

 being included in any genus previously described. 



216. ACM-ffiOPLEURA PARVULA Stimpson 



Plate XI, Fig. 4 



Acmccoplcuva parvula Stimpson. Proc. Acad. Nat. Sci. Phila.. x. p. 105 

 [51]. 1858. 



Carapax flat, broadest at the antero-lateral angles. Length to 

 breadth as i : 1.105. Surface smooth, except anteriorly, where it is 

 minutely rugate and moderately curving downward. ^ledian gas- 

 tric sulcus distinct. Front rather prominent, its margin somewhat 

 convex. Antero-lateral margin acute. Infraorbital crest broadl\- 

 3- or 4-lobed ; lobes smooth. Chelipeds equal, smooth externally ; 

 hand with three or four strong granules at the middle of the inner 

 surface and a lanose surface externally, between the bases of the 



