158 BULLETIN OF THE 



longitudinal, with three very distinct fissures on the outer side, which ex- 

 tend to the base of the orbital tube. Pterygostomi^n channel much nar- 

 rower than in Myra, strongly tridentate in front, and extending beyond 

 the orbit. External maxillipeds sharply granulated j exognath with a con- 

 vex outer margin, but much less dilated than in Myra; meros-joint of 

 endognath with a concave outer surface. Chelipeds of moderate length ; 

 hand much longer than the meros ; palm short, pyriform, much swollen 

 within toward the base, and somewhat twisted, though less so than in Ilia, 

 so that the fingers move in an oblique plane ; fingers much longer than the 

 palm, very thin and delicate, laminate, curving upward and inward toward 

 the tips, serrated on the outer edge, and armed within with numerous 

 needle-shaped teeth. Ambulatory feet naked (except the dactyli of the 

 posterior pair, which are sparsely pilose) ; penult joint compressed, with a 

 laminiform crest above and below ; dactyli lanceolate, those of the first 

 three pairs three-edged, those of the posterior pair two-edged and shorter 

 and broader than the others. 



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

 in the median line, 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 the water which bathes 

 the eggs or young in the abdominal cavity. 



In the male, all the joints of the abdomen, except the terminal one, are 

 soldered together. 



The genua resembles Myrodes somewhat in the character of the fingers, 

 but differs from it as well as from Myra and the allied genera in the want 

 of an indurated crest on the basal joint of the antennulae, and in the char- 

 acter of the dactyli of the ambulatory feet. From Persephona, etc., it dif- 

 fers in the convex outer margin of the exognath of the outer maxillipeds. 



Callidactylus asper nov. sp. 

 The following is a description of an adult female. Carapax con- 

 vex in the middle and posteriorly, but somewhat depressed toward the 

 interior margins. The sulci separating the gastric, cardiac, and intesti- 

 nal from the branchial regions are easily traceable, as well as that between 

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

 the intestinal regions. The hepatic region is surrounded by rather pro- 

 found depressions, and on its posterior part there is a strong tooth-like pro- 

 tuberance, occupying about one third its area. The upper surface of the 

 carapax is ornamented with scattered, prominent granules, or short, capi- 

 tate spinules, which become less prominent posteriorly and disappear alto- 

 gether near the posterior extremity, where the surface is covered with 

 e mailer and more crowded and depressed granules On the lateral parts 



