50 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



Second and third segments of male abdomen very broad, reaching 

 past the middle of the coxae of the last legs; fifth, sixth, and seventh 

 segments together subtriangular. 



Color. — Brownish red, the transverse ridges on the carapace and 

 the spines and margins of the chelipeds carmine red. (Hay and 

 Shore.) Surface silvery wherever the hairs are rubbed off by friction 

 (Verrill.) 



Habitat. — Hay ^° says of ttiis crab at Beaufort, "often taken in 

 the deeper channels of the harbor." 



Measurements. — Male (26104), total length of carapace 29, total 

 width 56.4, width between anterior bases of lateral spines 46.4, 

 fronto-orbital width 22.7, width across four frontal teeth 6.8 mm. 



Variation. — In the young the teeth of the outer pair of the front 

 are broader and blunter than in the adult, the lateral teeth show a 

 reduction in size in the fourth and sixth and sometimes in the second. 

 The bare, iridescent spots of the old are lacking. 



Range. — From southern Massachusetts to Texas. Venezuela. 



Material examined. — See table, pages 51-52. 



PORTUNUS (PORTUNUS) XANTUSU (Stimpson) 



Plate 18 



Achelous xantusii Stimpson, Ann. Lye. Nat. Hist. New York, vol. 7, 1860, p. 



222 [94] (type-locality, Cape St. Lucas; cotypes in M. C. Z.). 

 Neptunus xantusii A. Milne Edwards, Arch. Mus. Hist. Nat., Paris, vol. 10, 1861, 



p. 429; Crust. Reg. Mex., 1879, p. 213 (part), pi. 38, figs. 1-ld, not pi. 39, 



figs. 4-4c; San Diego, not Mazatlan and Chile. 

 Poriunus xantusii Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 593. 

 Portunus {Po7iumis) xantusii Rathbun, Bull. Amer. Mus. Nat. Hist., vol. 48, 



1923, p. 620 (part). 



Diagnosis. — Carapace twice as long as wide. Front not prominent; 

 teeth acute. Lateral spine about 3 tim^es as long as preceding tooth. 

 Merus of swimming legs spinulous. 



Description. — Carapace uneven. Surface of carapace and chelipeds 

 pubescent except on the elevations. Gastric region with a median 

 granulated ridge and two transverse ridges slightly concave forward; 

 on the branchial region an arcuate granulated ridge begins at the 

 lateral spine, curving forward and then inward opposite the seventh 

 lateral tooth; behind it two short, oblique parallel ridges; on the 

 cardiac region a transverse ridge interrupted at middle and forming 

 a T with a lower median ridge. Frontal teeth thick and narrow, not 

 projecting beyond the inferior orbital teeth, submedian teeth a little 

 narrower and usually a little more advanced than those of the outer 

 pair and a little further from them than from each other. Tooth at 

 inner angle of orbit bi dentate, outer tooth more advanced. Postorbital 



'0 Bull. Bur. Fisheries, vol. 35, 1915-16 (1918), p. 428. 



