514 BULLETIN 129, UNITED STATES NATIONAL MUSEUM 



Chelipeds very long and slender (tlie arm about 1.33 times width 

 of carapace), their upper surface finely rugose; an irregular row of 

 dentiform tubercles near middle of upper surface of arm and wrist 

 and nearer outer margin of hand; inner and outer margins of arm 

 and wrist with similar tubercles; upon upper margin of hand a series 

 of 18 or 20 irregular teeth, increasing generally in size to a point near 

 the fingers, where they diminish; on the outer margin 4 to 6 larger 

 teeth and many intermediate smaller ones. Legs long, for the 

 genus (first one reaching end of wrist), slender, bare and almost 

 smooth, having only some faint indications of spinules on upper 

 margins of merus joints. A conical spine or tubercle on each side 

 of sternum near base of chelipeds; another on coxal joint of chelipeds. 

 The second segment of abdomen has a sharp transverse crest, forming 

 a prominent lobe in the center and a tooth on each side. 



Measurements. — Male (15173), length of carapace 15.4, width of 

 same 18.6, length of arm 24.2 mm. 



Variation. — The rostrum may be broadly triangular, subentire, 

 instead of tridentate with marginal denticulations. In the young 

 the pterygostomian ridge is less developed anteriorly and the postor- 

 bital constriction is more evident, causing a resemblance to the 

 subgenus Rhinolarnbrus A. Milne Edwards.^^ 



Range. — North Carolina; Gulf ol Mexico along the coast of Florida 

 to Florida Straits and Cape Florida; West Indies; Trinidad. Depth, 

 25 to 115 fathoms. 



Material examined. — See table, page 515. 



PARTHENOPE (PARTHENOPE) HYPONCA (Stimpson) 



Plate 275, figs. 4-6 



Lambrus hyponcus Stimpson, Ann. Lye. Nat. Hist. New York, vol. 10, 1871, 

 p. 100 [127], (type-locality, Panama; type not extant). — A. Milne Ed- 

 wards, Crust. R^g. Mex., 1878, p. 153, pi. 30, figs. 3-36. 



Parthenope (Parihenope) hyponcus Rathbun, Proc. U. S. Nat. Mus., vol. 38, 

 1910, p. 576. 



Diagnosis. — Carapace broadly ovate. Rostrum broadly triangular 

 at extremity. Merus joints of ambulatories with entire margins 

 except extremity of fourth; dactyli naked. 



Description. — Carapace subrhomboidal, posterior region being well 

 developed and prominent. One low tubercle on gastric region, two 

 large, prominent ones on cardiac region, one small, spiniform one on 

 posterior margin at median line, and two rather large ones on branchial 

 region, the posterior of which is taller and close to postero-lateral 

 margin. Besides these tubercles there are several other, minute ones, 

 roughly arranged in 8 or 10 longitudinal rows. General surface 

 covered with crowded punctures ; two or three small pits in depression 



" Crust. R6g. Mex., 1878, p. 148. 



