THE SPIDER CRABS OF AMERICA 129 



completely filled by the outer maxillipeds ; ischium with its inner 

 distal portion strongly advanced; merus cordate, with a prominent 

 narrow lobe on the inner side. Chelipeds of moderate length , merus 

 triangulate, manus swollen, fingers long and curving inward. Am- 

 bulatory legs very long and slender, cylindrical, decreasing succes- 

 sively in length from first to fourth pair; dactyli long and slightly 

 curved. Abdomen of male with the last two segments, of female 

 with the last three segments, fused. 



Not found outside of America, where it ranges from North Carolina 

 to Florida Straits and Gulf of Mexico; and from Monterey Bay, 

 California, to Panama. 



KEY TO THE SPECIES OF THE GENUS PYROMAU. 



A'. A spine near middle of basal antennal article. Ambulatory legs long, first 

 leg in male three or more times as long as carapace. 

 Bi. Rostrum tapering regularly to tip. Chelipeds and legs covered with short, 

 soft pubescence. No spine at proximal end of merus of ambulatory 



legs cuspidata, p. 129. 



B-. Rostrum triangular at base, then narrowing to a slender spine. Chelipeds 

 and legs not noticeably pubescent. An erect spine at proximal end of 

 merus of ambulatory legs; a short fringe of hair on either side of the 



dactjds arachna, p. 131. 



A2. No spine near middle of basal antennal article. Ambulatory legs shorter 

 than in A^, first leg in male usually not much over twice as long as 

 carapace. 

 B'. Two large median gastric tubercles. Granules few; greater part of cara- 

 pace smooth. Legs unusually long and slender, but less than three 



times as long as carapace tuberculata, var. A., p. 136. 



B^. Not more than one large median gastric tubercle. Granules more numer- 

 ous than in B'. 

 C*. One large median gastric tubercle. Granules not nearly covering 

 carapace. Rostrum longer, or just as long, as wide. 



tuberculata, typical, p. 133. 

 C^. No large median gastric tubercle. Granules coarse, almost covering 

 carapace. Rostrum short, wider than long. 



tuberculata, var. B., p. 136. 



PYROMAIA CUSProATA Stimpson 



Plate 41 



Pyromaia cuspidata Stimpson, Bull. Mus. Comp. ZooL, vol. 2, 1871, p. 110 



(type-localities, off Sand Key, 82 fathoms; off Alligator Reef, 88 fathoms; 



off the Samboes, 93 and 121 fathoms; S. W. of Sand Key, 125 fathoms; 



types not extant). — A. Milne Edwards, Crust. R4g. Mex., 1879, p. 197; 



pi. 36, figs. 2-2/.— Rathbun, Proc. U. S. Nat. Mus., vol. 17, 1894, p. 73 



(part).— Hay and Shore, Bull. Bur. Fisheries, vol. 35, 1915-16 (1918), 



p. 455, pi. 38, fig. 4. 

 Apiomaia cuspidata von Martens, Zool. Rec, 1871 (1S73), p. 182. — Miers, 



Journ. Linn. Soc. London, vol. 14, 1879, p. 651. 



Diagnosis. — Four (or five) spines on branchial margin. Six median 

 spines or large tubercles on carapace. Rostrum tapering rather regu- 



