378 FEESH WA TEB CRA BS FROM COSTA RICA—M. J. RA THB TJX. 



VOL. XVIII. 



Fig. 2. 



LARGE HAND OF PSEUDOTHELPHCSA MAGNA. 



About three-eighths naturnl size. 



inner side of the lower portion, shown in Figure 10, is mncli longer than 

 the corresponding part in P. rkhmondi. The merns of the outer maxil- 

 lipeds is longer and narrower in this species.^ 



Chelipeds unequal, large and strong. The raerus has a row of very 

 stout conical teeth on its inner margin, as a rule becoming smaller 

 proximally and continued on the ischium ; the lower edge has a row of 



small tubercles ; • the outer 

 nmrgin has a wide band of 

 prominent squamose tuber- 

 cles, which, toward the car 

 pus, become rugo.se lines. 

 The palmar portion of the 

 manus is longer than in 

 P. richmondi, the margins 

 of its surface less convex. 

 The outer surface of carpus, 

 propodus and dactylus is covered with a network of dark brown, and 

 numerous granules of still darker color. The teeth of the fingers have 

 a dark band across their bases ana a lighter line around their cutting- 

 edges. Ambulatory legs thick, meri with edges rough or slightly spinu- 

 lous. Inner lower margin of meri of first pair with prominent tubercles. 

 This margin is smooth in P. richmonili. 



Dimensions. — Largest male, length 84 mm., width 135 mm. 

 Color. — Yellowish brown. 



Habitat. — Pozo Azul, 800 or 1,000 feet above the sea, two males (Nos. 

 19048, 10049, type, U. S. K M.) collected by J. C. Zeledon, April 4, 1888; 

 Eio Maria Aguilar, one male, collected by A. Lizauo, 

 May 29, 1891 ; also one female (Xo. 19050, U. S. X. M.) 

 collected by J. Fid. Tristan; Eio Torres, one male, 

 collected by J. Fid. Tristan. 



This species is the largest of the known Pseudo- 

 thelphusidtx'. 



PSEUDOTHELPHUSA TRISTANI, new species. 

 (Plate XXX, figs. 1-5.) 

 smooth and shining, inconspicuously 



Carapace 

 granulate near the lateral margins; grooves deep; 

 branchial region nnich swollen in its anterior half. 

 Front with a well-marked crest, which is rough with 

 punctai but not tuberculate, and terminates at the 

 orbital border just behind the insertion of the eye. 

 margins with a prominent punctate ridge. Outer half of the superior 

 orbital border finely crenulate ; inferior border crenulate. Anterolateral 

 margin denticulate, and with two well-marked teeth behind the orbit. 



1 Compare fig. 1 in text with fig. 9, pi. lxxv, Vol. XVI, Proceedings U. S. National 

 Museum. 



Fig. 3. 

 OUTER 51AXILLIPED OF 



PSECDOT H E L r H I' S A 



TRISTANI. 

 About four times natural iiie. 



Lower and outer 



