270 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



Diagnosis. — Chelipeds with a large hole above between carpus and 

 manus. Lobes of front very oblique, edge concave. Color of fixed 

 finger encroaching very slightly on palm. 



Description. — Carapace naked above, areolated; areolets protu- 

 berant, somewhat wartlike and granulated ; gastric and epibranchial 

 regions very prominent. Lateral teeth small, spiniform, their inter- 

 spaces armed with denticles, two or three in number. Front strongly 

 projecting at middle and bilobed, margin of lobe concave, inner end 

 rectangular, outer end spiniform. Peduncle of eye granulated, a few 

 spinules at summit. Orbit with the margin sharply granulated above, 

 two closed fissures faintly indicated, no tooth at upper inner angle; 

 two or three spinules below near outer side and a spine at lower inner 

 angle. Exposed portion of outer maxillipeds, except dactyls, orna- 

 mented with bead granules. 



Chelipeds when retracted having a large hole above between the 

 carpus and manus for the passage of water to the afl'erent branchial 

 apertures. Near the middle of the inner surface of the manus are 

 two unequal peglike spines, which form in retraction a sort of filter 

 before the branchial opening. 



Carpus and hand sculptured externally with granulated protu- 

 berances which on the hand are arranged in four or five longitudinal 

 rows; hand serrated above with four teeth, partially joined by a thin 

 web; fingers stout, short, less than half as long as palm. Legs thickly 

 hairy below; carpus and propodus armed posteriorly with acorn- 

 shaped spines. 



Measurements. — Male (15006), length of carapace 13.2, width of 

 same 16, fronto-orbital width 9.5, width of front 5.6 mm. 



Range. — Oft" North Carolina to Mexico. 



Material examined. — See table, page 27L 



Genus LIPAESTHESIUS Rathbun 



Lipaesthesius Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 584; type, L. 

 leeanus Rathbun. 



Anterior portion of carapace very broad, posterior fourth veryi 

 narrow; anterior half very convex longitudinally, posterior half 

 flattened. Antero-lateral margin arcuate, running obliciuely down- 

 ward to angle of buccal cavity. Front deflexed, forming a projecting 

 hood over the antennules. Orbits small, subcircular, without 

 sutures. The anterior margin of the basal antenna! article is joined 

 to the downward prolongation of the front, only the flat lower surfacei 

 of the article being exposed to view. The epistome has a deep: 

 transverse invagination through its entire width. Abdomen of male< 

 with third to fifth segments fused. Chelipeds concave on inner sidej 

 to fit closely against carapace. Last pair of legs fitting into postero- 

 lateral sinus of carapace. 



One species only. 



