THE SPIDER CRABS OF AMERICA 429 



coryphe. Five of the smallest gastric tubercles form a transverse 

 row. Oblique branchial grooves deep, but more longitudinal than 

 in coryphe. Antero-lateral projections consisting of two lobes 

 followed by a spine at the lateral angle; all are hooked forward at the 

 tip. A postlateral spine is followed by two dorsal tubercles in the 

 same line. Anterior edge of basal segment of antenna deeply 

 bilobed, lobes equally advanced with the rostrum. 



Chehpeds wider than in coryphe; arm with only one lobe, which 

 may be feebly bilobed, on inner margin, 4 spines on outer margin, 

 and on distal half two or three tubercles above and one below; 6 

 well-marked tubercles on dorsal surface of wrist and 2 on inner edge 

 which is laminate; manus short and high; immovable finger horizontal; 

 interdigital sinus triangular; a tooth at proximal two-fifths of dactylus, 

 prehensile edges crenulate at the tips. Legs very rough with spines 

 above and furnished with coarse setae; merus joints with from 1 to 3 

 tubercles below, of last pair with tubercles also on posterior surface. 



Color. — Plumbeous, passing into fuscous (Bell) . 



Measurements. — Male (3209), entire length of carapace 13, width 

 including spines 19 mm. 



Range. — -Lower California to Ecuador. 



Material examined. — 



Cape St. Lucas; John Xantus; 1 male, 1 young female (1241, 

 M. C. Z.). 



Panama; Capt. J. M. Dow; 2 males, 1 female (3209). 



Perico Island, Panama; October 26, 1904; Albatross; 1 male, 1 

 female (33388), 1 male (M. C. Z.). 



MITHKAX (MITHRACULUS) NODOSUS Bell 



Plate 155 



Mithrax nodosus Bell, Proc. Zool. Soc. London, vol. 3, 1835, p. 171 (type- 

 locality, Galapagos Islands; type not extant); Trans. Zool. Soc. London, 

 vol. 2, 1836, p. 53, pi. 11, figs. 1-16. 



Mithraculus nodosus White, List Crust. Brit. Mus., 1847, p. 7. — A. Milne 

 Edwards, Crust. R^g. Mex., 1875, p. 108, pi. 23, figs. b-5d. 



Mitraculus ruber Cano, Boll. Soc. Nat. Napoli, ser. 1, vol. 3, 1889, p. 185. 

 Not Mithraculus ruber Stimpson. 



Diagnosis. — Three large lobes on antero-lateral margin. Posterior 

 part of carapace eroded. Inner edge of cheliped (to middle of manus) 

 laminate. 



Description. — Allied to M. coryphe. Carapace narrower, rostral 

 teeth narrower and more deeply separated; the pair of tubercles 

 behind them subacute; 7 small, gastric tubercles in 2 transverse 

 rows of 2 and 5; inner supra-orbital angles narrow, lobiform, pro- 

 minent; outer angles not dentiform nor pronounced; 3 antero-lateral 

 lobes larger than in coryphe, the first one close to the orbital angle; a 

 5487— 25t 29 



