96 CALIFORNIA ACADEMY OP SCIENCES. 



Genus Cryptophrys Rathbun. 



Carapace subpentagonal, hard, convex, not much broader than long. 

 Front produced. Orbits nearly circular and lodged in the sides of the 

 front, only a small part of them visible from above. Antennules oblique 

 or transverse. Buccal area much carved. Maxillipeds very oblique, the 

 distal extremities (not as is usual the inner margins) being opposite each 

 other and separated by a space in which the palpi are lodged; ischium 

 rudimentary; merus large and curved; palp two-jointed and joined to the 

 antero-external angle of the merus. Chelipeds moderately stout, the palm 

 in the male broad and inflated. Ambulatory legs compressed; first three 

 pairs subequal; fourth pair shortest. The base of the abdomen in the 

 male does not cover the whole of the last thoracic sternum. 



Type. — C. concharum Eathbun. 



Cryptophrys concharum Rath. 



Cryptophrys concharum Rathbun M., Proc. U. S. Nat. Mus., Vol. XVI, 

 1893, p. 250. 



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

 gastric region but no longitudinal sulci as in pubescens. Front emargin- 

 ate. Antennules large, nearly transverse. Ocular peduncles short, stoiit, 

 and completely filling the orbits. Antero-lateral margins marked by a 

 ciliated line. Sides of the carapace broadly rounded. Merus of the max- 

 illipeds 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 overreaching 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 

 segments 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. 



False Bay, San Diego County, Calif., from the mantle 

 of Mya arenaria L. and Puget Sound from the mantle of 

 Cardita borealis Conrad (Miss Rathbun). San Diego! 



Described from specimens from Puget Sound kindly 

 sent me by Miss Rathbun. A specimen I collected at 

 San Diego was found on the beach free from any host. 



