THE CANCROID CRABS OF AMERICA 535 



Carapace thick, swollen, suborbiciilar, narrow behind. Regions 

 well marked, little prominent. Front bilobed and deflexed. Orbits 

 deep, almost circular, superior emarginations typically replaced by 

 closed fissures. Antero-lateral margins little oblique, prolonged in- 

 ward and backward from the last lateral tooth by a small crest on the 

 branchial regions. Basal article of outer antennae remarkably short, 

 second article scarcely reaching the subfrontal prolongation; flagel- 

 lum short. Basal article of inner antennae wide and raised, the 

 fossette in which the remaining articles are folded is oblique. The 

 buccal cavity bears on either side a small emargination correspond- 

 ing to an endostomial crest which limits the canal of the branchial 

 chamber. Outer maxillipeds wide; merus rounded at external angle 

 and slightly cut inside for insertion of palp. Chelipeds subequal, 

 short and strong; arm entirely concealed under carapace; three large 

 lobes or tubercles on upper margin of palm. Last three articles of 

 ambulatory legs rounded above, dactyli terminated by slender, 

 pointed nails. Abdomen of male with seven free segments. 



Panama to Chile; southern Florida and West Indies; Argentina to 

 Straits of Magellan. 



KEY TO THE SPECIES OF THE GENUS PttUMNOlDES 



A'. Carapace and chelipeds not thickly covered with hair. A large tubercle on 

 outer surface of immovable finger. 



B'. Branchial ridge almost transverse perlatus, p. 535. 



B2. Branchial ridge almost longitudinal hassleri, p. 537. 



A2. Carapace and chelipeds thickly covered with hair. No large tubercle on 

 outer surface of immovable finger nudifrons, p. 538- 



ANALOGOUS SPECIES ON OPPOSITE SIDES OF THE CONTINENT 



Atlantic Pacific 



hassleri perlatus 



PILUMNOIDES PERLATUS (Poeppig) 



Plate 216; Plate 217, Figure 3; Plate 218, Figure 3 



Hepatus perlatus Poeppig, Arch. f. Naturg., vol. 2, pt. 1, 1836, p. 135, pi. 4, 

 fig. 2 (type-locality, St. Vincent Bay, near Talcahuano, Chile; type in Mus. 

 Univ. Leipzig). 



Pilumnoides perlatus Milne Edwards and Lucas, d'Orbigny's Voy. I'Am^r. 

 M^rid., vol. 6, pt. 1, Crust., 1844, p. 21; atlas, vol. 9, 1847, pi. 9, figs, l-lc— 

 A. Milne Edwards, Crust. R6g. Mex., 1880, p. 304, pi. 54, figs. 6, 6a. — 

 Rathbun, Revista Chilena Hist. Nat., vol. 11, 1907, p. 49, pi. 2, figs. 1 and 

 2; Proc. U. S. Nat. Mus., vol. 38, 1910, p. 544, pi. 50, fig. 2. 



Pilumnoides danai Kinahan, Journ. Roy. Dublin Soc, vol. 1, 1857, pp. 333 and 

 337, pi, 14, fig. 2 (type-locality, Chinchas Islands, Peru, 7 fathoms; tjpe 

 in Mus. Roy. Dublin Soc). 



Diagnosis. — Branchial ridge almost transverse. Short transverse 

 granulated ridges on anterior part of carapace. 



Description. — Carapace broader than long, anterior two-thirds 

 tuberculate, the tubercles forming, in part, short transverse striae, 



