1917 Way; on Taxonomy of Crabs 361 



2. Pinnotheres concharum Rathbun, in forthcoming work, (not figured) 

 Cryptophrys cori-charum Rathbun, in Proc. U. S. Nat. Mus. 16:250. 

 1893. 



"Carapace smooth, slightly longer than broad ; a faint sulcus behind 

 the gastric region but no longitudinal sulci as in (C) puhescens. Front emar- 

 ginate. Antennules large, nearly transverse. Ocular peduncles short, stout 

 ^nd completely filling the orbits. Antero-lateral margins marked by a cili- 

 ^ited line. Sides of the carapace broadly rounded. Merus of the maxilli- 

 peds with the outer margin curved, the distal portion almost transverse ; 

 the last joint of the palp four-sided, the extremity widened. Chelipeds 

 -and ambulatory legs margined by a row of coarse hairs. Ambulatory legs 

 widened and quite strongly compressed ; second pair a little longer than 

 the others ; fourth pair over reaching the carpus of the preceding pairs ; 

 dactyls short,- terminating in slender, curved, corneous tips. Abdomen in 

 the male widest at the second joint; the large, compound segment has the 

 margin at first convex and then slightly concave ; the two following seg- 

 ments broader than long; terminal segment subrectangular but distally 

 rounded ; the last two segments may be partly coalesced. Length, 4.7 mm. ; 

 breadth, 4.2 mm," (Holmes, 1900.) 



The specimens have been found in Friday Harbor region by Professor 

 Kincaid. No specimens were found during the summer of 1916. Miss 

 Rathbun has reported that they are found in the mantles of Mya arenaria, 

 ^'ardita borealis and Mytilus edulis. 



Genus Pinnixa 



KEY TO SPECIES 



A. Dactyls of third pairs of walking legs straight. 1. P. tubicola 



AA. Dactyls of third pairs of walking legs curved. 2. P. littoralis 



1. Pinnixa tubicola Holmes. (fig. 13) 



Rostrum none ; antennae small, inconspicuous ; carapace smooth, more 

 than twice as wide as long, strongly curved and bent downwards, both 

 laterally and anteriorly; "a shallow, transverse depression behind the 

 •gastric area, behind which is a convex (not crested) transverse intumescence 

 from which the carapace curves sharply downwards, towards the broad, 

 slightly concave posterior margin. Front short, deflexed, not projecting 

 beyond the general contour of the carapace" ; maxillipeds pubescent ; fringe 

 of hair on the anterior margins on either side of the eyes. Chelipeds 

 •short but rather stout; merus with a rounded plate-like projection at the 

 •distal end on the inner surface ; hand inflated ; dactyl and pollex slightly 

 hooked, inner margin meeting when closed. First pair of walking legs 

 slender; merus long, about equal to the combined length of propodus and 



