76 CALIFORNIA ACADEMY OF SCIENCES. 



much wider behind; by the narrower abdomen in the 

 male with the shorter second segment; by the more 

 slender fingers in the large cheliped, and the more 

 slender merus joints in the ambulatory legs. It may be 

 distinguished from coloradensis Rathbun by its darker 

 and more convex carapace, the more slender merus joints 

 in the ambulatory legs, and by the different curvature of 

 the upper side of the palm in the large cheliped. It is 

 a much smaller species than brevifrons Stimpson, and 

 has a relatively wider and more convex carapace and 

 very different upper orbital margins. 



Uca rectilata (Lock.) 



Gelasimus rectilatus Lockington, Proc. Cal. Acad. Sci., Vol. VII, 1877, 



p. 148. 

 Gelasimus annulipes Kingsley (not Milne-Edwards), Proc. Acad. Nat. Sci. 



Phila., 1880, p. 148. 



Carapace wide, nearly flat transversely, but longitudinally strongly 

 convex. Front broad and arched strongly forwards. The upper edge of 

 the superior orbital margin is strongly curved; the lower edge runs close 

 to the upper but is distinct; the lower margin of the orbit is prominently 

 denticulated, especially at the rounded outer angle. Postorbital angle 

 prominent, acute, and directed obliquely outwards; the lateral margins of 

 the carapace are straight, converging from the postorbital angles to the 

 straight posterior margin. Maxillipeds with the ischium large, smooth, 

 strongly convex; merus oblique, much wider than long, but narrower than 

 the ischium and about one-third its length. A longitudinal groove on 

 either side of the buccal area. Merus of the larger cheliped but slightly 

 rugose with the angles rounded; carpus lightly granulated on the upper 

 surface; hand similar to that of crenulata; the outer surface of the palm 

 finely granulated and the lower edge margined; an oblique, granulated 

 ridge on the inner surface extending from the lower margin to the deep 

 carpal groove; no oblique ridge above this one as in crenulata; two parallel 

 lines of granules behind the articulation of the dactyl, the posterior of 

 which is continued upon the poUex; pollex tapering, a tooth near the 

 middle, the extremity slightly excavated; dactyl curved more strongly 

 toward the tip, which slightly overreaches the pollex. Ambulatory legs 

 slender. Abdomen of the male seven-jointed, the first two joints short. 



