THE CANCROID CRABS OF AMERICA 57 



Neptunus xantusii A. Milne Edwards, Crust. Rdg. Mex., 1879, p. 213 (part), 



pi. 39, figs. 4-4c; Mazatlan. 

 Neptunus transversus A. Milne Edwards, Crust. Reg. Mex., 1879, p. 220. 

 Portunus transversus Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 592. 

 Portunus (Portunus) transversus Rathbun, Proc. U. S. Nat. Mus., vol. 38, 1910, 



p. 577. 



Diagnosis. — Densely pubescent. Lateral spine as long as the mdth 

 of the next four teeth. Superior spine of manus at distal fourth 

 (in female). 



Description of female {22025). — The largest specimen is a mature 

 female. Carapace 2)i times as broad as long; surface pubescent. 

 The long branchial ridge similar to that of acuminatus, the next short 

 ridge is formed by a broad band of coarse granules. The lobule 

 at the inner angle of the branchial region is deeply defined. Both 

 pairs of frontal teeth are triangular, deeply separated, similar, those 

 of middle pair somewhat smaller and more advanced than those of 

 outer pair. Of the lateral teeth the third is the widest, its outer mar- 

 gin somewhat angled; the lateral spine is of good length, as long as 

 the width of the next four teeth, its carina is directed a little forward. 

 The chehped (the right is missing) is not more that 2^ times as 

 long as carapace and is rather heavy, merus armed on inner margin 

 with 7 spines, the proximal one very small, distal interval doubly 

 wide. Inner spine of wrist subequal to proximal spine of palm; 

 subterminal spine of palm at distal fourth of upper margin. Sternum 

 and abdomen pubescent. 



Measurements. — Female (22025), total length of carapace 34.7, 

 width of same 77.2, width to anterior base of lateral spines 56.2; 

 fronto-orbital width 26.1, \vidth of front 8.5 mm. 



Additional material. — The specimen next in size, a female (3267), 

 is broken but is about 59 mm. wide. All the margmal teeth and 

 spines are relatively narrower than in the specimen above described; 

 the lateral spine is as long as the width of the next three teeth and is 

 strongly curved forward. The merus of the left chehped (the right 

 is missing) bears only 5 spines. 



A female cotype in the Paris Museum was loaned for comparison 

 through the courtesy of Doctor Gravier. The abdomen is mature in 

 form but the size small: Total length of carapace 19.3, width of same 

 39.4, width between base of lateral spmes 30.6, fronto-orbital wddth 

 16.2, width of front 5 mm. Outer pair of frontal teeth defmitely 

 larger than inner pair; lateral teeth corresponding to those described 

 for female No. 22025; lateral spine as long as the width of the next 

 3}2 teeth; merus of cheliped armed with five inner spmes; the wrist 

 and palm are hke those of the large female described. It should be 

 noted that the right natatory foot of the specimen does not pertain 

 to it and was attached by mistake. (See plate 2.) It is larger 



