GRAPSIDAE. 31 



Ptychognathus easterana, sp. nov. 

 PI. 2, Fig. 4; PI. 7, Figs. 4, 4 a. 



Male. — Carapace distinctly broader than long, broadest at the posterior 

 of the lateral teeth, slightly convex in an antero-posterior as well as a 

 transverse direction. Surface with a deep median H-form depression, 

 and numerous irregular pits, some of which define the hepatic region. 

 Anterior and lateral portions very finely granulate. Entire upper surface 

 punctate and finely veined. 



Fronto-orbital width about |, and front about f , the greatest width of 

 the carapace; edge of front sinuous; orbital margin sinuous and directed 

 distinctly backward toward the outer angle. 



Two lateral teeth, marked by triangular notches, the posterior the 

 smaller; distance between tips of teeth | the distance between the first 

 tooth and the orbital tooth. The branchial ridge arises as far behind 

 the second of the lateral teeth as those teeth are distant from each other ; 

 the ridge or granulated line is bent at first ' strongly inward, then turns 

 strongly backward. 



The edge of the front, viewed from before, is curved upward. 



The outer maxilliped is much like that of P. polleni de Man, 1 but 

 the merus of the endognath has a greater outer extension. The abdomen 

 of the c? resembles also that species (op. cit., fig. 20 b), but the sides of the 

 terminal segment are more divergent at the base. 



Chelipeds finely granulate. Wrist with blunt inner angle. Chelae 

 without the patch of hair so conspicuous in some species. Immovable 

 finger with a deep longitudinal groove, which at the base of the finger 

 turns upward on the palm. Fingers with a moderate gape ; dactyl with 

 many teeth, the basal one a little larger. Teeth of pollex, 3 large, and 

 1 or 2 small at basal end. Horny, spoon-shaped extremities of fingers, 

 bordered proximally with a row of short hairs. 



Last 3 joints of feet with short setae on the edges ; meral joints setose 

 at the extremity, with transverse bands of color. 



Dimensions: — £, length 10.6 mm., width 12.7 mm.; fronto-orbital 

 width 11 mm., width of front 4.7 mm. 



Type locality: — Easter Island; shore; Dec. 20, 1904; 1 $ (Cat. 

 No. 32,845, U. S. Nat. Mus.). 



1 Zool. Jahrb., Syst, 1808, 10, pi. 28, fig. 20 a. 



