OXYSTOMATOUS AND ALLIED CRABS OF AMERICA J 93 



short, basal article of antennules not indurated. Orbit longitudinal, 

 with three very distinct fissures on the outer side, which extend to the 

 base of the orbital tube. Pterygostomian channel strongly tridentate 

 in front and extending beyond the orbit. Outer maxillipeds sharply 

 granulated; exognath with a convex outer margin, little dilated; 

 merus of endognath with a concave outer surface. Chelipeds of mod- 

 erate length; chela much longer than merus; palm short, pyriform, 

 much swollen within toward the base, and somewhat twisted, so that 

 the fingers move in an oblique plane; fingers much longer than palm, 

 very thin and deHcate, laminate, curving upward and inward toward 

 the tips, serrated on outer edge, armed within with numerous needle- 

 shaped teeth. Ambulatory legs naked, except the dactyli which are 

 sparsely pilose; propodus compressed, with a laminiform crest above 

 and below; dactyh lanceolate, those of first three pairs 3-edged, those 

 of posterior pair 2-edged and shorter and broader than the others. 



In the female there is a deep, smooth channel on the outer maxil- 

 lipeds, between and on the ischium joints, defined on either side by a 

 strong ciliated ridge. This channel does not exist in the male and has 

 doubtless something to do with the flow of water which bathes the 

 eggs or young in the abdominal cavity. (After Stimpson.) 



Contains only one species, 



CALLIDACTYLUS ASPER Stimpson 



Plate 58, Figures 1-3 



Callidactylus asper Stimpson, Bull. Mus. Comp. Zool., vol. 2, p. 158, 1871 (type 

 localities, three stations in Florida Kej^s, 16 to 37 fathoms; types not extant). 



Diagnosis. — Carapace furnished with 11 or more spines. Exognath 

 of outer maxilliped with convex margin. Fingers rough on both edges. 

 Dactyli of first three pairs of legs 3-edged, of posterior pair 2-edged. 



Description. — The sulci separating the gastric, cardiac, and intes- 

 tinal from the branchial regions are easily traceable, as well as that 

 between cardiac and gastric; but there is none between cardiac and 

 intestinal regions. Hepatic region surrounded by rather profound 

 depressions, and on its posterior part there is a strong toothlike 

 protuberance occupying about one-third its area. Upper surface of 

 carapace ornamented with scattered, prominent granules or short, 

 capitate spinules which become less prominent posteriorly and dis- 

 appear altogether near the posterior extremity, where the surface is 

 covered with smaller and more crowded and depressed granules. 

 On the lateral parts of the branchial region the two kinds of granules 

 are found together. In the median line there are three or four short 

 blunt spines on the posterior part of gastric and cardiac regions, the 

 posterior one of which is rather remote from the others and much 

 larger, nearly as large as the median posterior spine. A strong 

 triangular tooth pointing forward, on subhepatic region, and a smaller 



