58 BULLETIN 152, UNITED STATES NATIONAL MUSEUM 



than the corresponding left leg, its articles are of different shape, the 

 ischium being absent, and appears to belong to another species. 



The smaller specimens in the United States National Museum, five 

 in number, four male and one female, are immature with the exception 

 of one male. They resemble one another in most respects but differ 

 from female 22025 in having the frontal teeth less triangular, more 

 oblong and with arcuate margins, the sinuses correspondingly narrower. 

 There is some variation in length of lateral spines; the smallest speci- 

 men (male 22025) 12 mm. long having the longest, straightest, and 

 most transverse spines, 4 mm. long, as long as the four adjacent 

 teeth. The mature male (61332), length 24.7 mm. has the most 

 curved spine, curvature intermediate between the two mature females, 

 length of spine 6.6 mm., a little longer than the width of the three 

 adjacent teeth; meral spines 6 left, 5 right, terminal segment of 

 abdomen about three-fourths as long as sixth segment. The four 

 immature specimens show only 4 spines on the arm. 



Range. — Mazatlan and Manzanillo, Mexico; Panama; Chile. 



Material examined. — 



PANAMA.— Capt. J. M. Dow; 1 female (3267). 



Island at end of breakwater, Panama Bay; Februarj'^ 5, 1912; 

 Meek and Hildebrand; 2 males (1 young) (61332). 



Panama Bay; March 30, 1888; Albatross: Lat. 8° 51' 00" N., 

 long. 79° 31' 30" W.; 7 fathoms; gn. M.; station 2800; 1 young 

 male, 1 female (22025). Lat. 8° 38' 00" N., long. 79° 31' 30" W.; 

 16 fathoms; gn. M.; station 2802; 1 young male, 1 young female 

 (61333). 



CHILE. — Coast of Chile; Fontaines collector; 1 female cotype 

 (Paris Mus.). 



PORTUNUS (PORTUNUS) PANAMENSIS (Stimpson) 



Plate 20, Figure 1; Plate 22, Figure 3; Plates 23 and 24 



Achelous panamensis Stimpson, Ann. Lye. Nat. Hist. New York, vol. 10, 1871, p- 



112 [22] (type-locality, Panama; type in M.C.Z.). 

 Amphitrite paucispinis Lockington, Proc. California Acad. Sci., vol. 7, 1876 



(1877), p. 107 [13] (type-localities, Angeles Bay and Mulege Bay, both in 



the Gulf of California, and Magdalena Bay, west coast of Lower California; 



types not extant). 

 Neptunus panamensis A. Milne Edwards, Crust. R6g. Mex., 1879, p. 219. 

 Poriunus panamensis Rathbun, Proc. U. S. Nat. Mus., vol. 21, 1898, p. 592. 

 Portunus {Poriunus) acuminatus Rathbtjn, Proc. U. S. Nat. Mus., vol. 38, 1910, 



pp. 538 and 577, pi. 49, fig. 4; not Achelous acuminatus Stimpson. 

 Poriunus (Poriunus) panamensis Rathbun, Proc. U. S. Nat. Mus.. vol. 38, 1910, 



pp. 577 and 610. 



Diagnosis. — Lateral spine as long as two adjacent teeth and part of 

 a third. Cheliped of male over 3 times as long as carapace. Superior 

 spine of manus at distal sixth in male. 



Description. — Covered with a very short pubescence. Carapace 

 twice as broad as long and regardless of lateral spines is sensibly 



