88 CALIFORNIA ACADEMY OF SCIENCES. 



abruptly downwards, having no trace of a median or transverse groove. 

 Eye-stalks short, stout, rounded and lodged in nearly circular orbits. 

 Antennules obliquely plicated in very wide fossettes. Antennae minute. 

 Maxillipeds very oblique; merus large, smooth, curved and distally 

 rounded; the penultimate joint of the palp is broad, flattened, and bears 

 the minute third joint near the middle of the inner margin. Chelipeds 

 smooth and rather slender; hand long and narrow; palm about twice as 

 long as wide, with the upper and lower margins parallel, and having one 

 or two rows of hairs below, one of which reaches to the tip of the finger; 

 fingers longitudinal, subcylindrical, nearly straight, and shorter than the 

 palm; dactyl with a tooth a little behind the middle of the inner margin. 

 Legs slender, glossy, and nearly naked, but the upper side of the merus 

 and the lower side of the propodus are generally more or less pubescent; 

 dactyls pubescent, about half the length of the propodi, and subuncinate 

 at the tip. Color in life, whitish; carapace and abdomen largely covered 

 with orange. 



Length of carapace, female, 11.5 mm.; width, 13 mm. 



The following measurements are given by Dana from his specimen from 

 Puget Sound: Length of carapace, 5.75 lines; breadth, 6.75 lines; breadth 

 between post-frontal sutures, 2.25 lines; length of third joint of fourth 

 pair of legs, 2.75 lines, or about two-fifths the breadth of the carapace. 



Queen Charlotte Is. (Smith), Puget Sound (Dana), 

 Farallon Is. and San Diego (Lockington), San Pedro! in 

 shell of Tapes. It is found also in the shell of Packy- 

 desma crassitelloides and sometimes in the tests of 

 Echini. 



Genus Pinnixa White (emended). 



Carapace much wider than long. Front narrow, nearly transverse. 

 Orbits broadly ovate or nearly circular, with a wide inner hiatus which is 

 partly occupied by the basal antennal joints. Antennules transversely or 

 obliquely plicated in wide fossettes which communicate with each other 

 beneath the front. Eye-stalks very short. Epistome linear-transverse. 

 Ischium of the maxillipeds small; merus large, the distal portion of the 

 outer margin convex; palp joined to the summit of the merus, the third 

 joint joined on the inner side of the preceding one near the base. Cheli- 

 peds of moderate size; merus trigonous; carpus smooth; hand large, com- 

 pressed. Second ambulatory legs larger than the first; the third pair is the 

 largest of all; fourth pair much shorter than the third and relatively 

 stouter than the first and second. • The abdomen in both sexes is seven- 

 jointed and narrower at the base than the width of the last thoracic 

 sternum. 



Type. — P. cylindrica Say. 



