160 CALIFORNIA ACADEMY OF SCIENCES. 



margin produced into a thin expansion overhanging the smooth inner 

 surface; lower margin produced in a similar manner but not nearly so 

 strongly; posterior margin below the articulation of the merus produced 

 backwards into a broadly and evenly rounded lobe; hand narrower and a 

 little shorter than the carpus, broadest at the base, with the ciliated mar- 

 gins more or less incurved towards the proximal end; a prominent hiatus 

 between the fingers; a prominent upturned tooth between the bases of the 

 fingers; fingers a little longer than the palm and furnished with tufts of 

 cilia; dactyl longer than the pollex, minutely denticulated on the inner 

 margin, and bent abruptly near the tip, forming a sharp hook. In the 

 smaller cheliped the ischium resembles that of the larger one but is 

 scarcely denticulated below; merus widest near the middle, shorter than 

 the ischium, and devoid of the lobe at the base, but having an obsolescent 

 tooth near the middle of the lower margin; carpus very long and narrow, 

 with both surfaces convex; hand narrow, relatively much longer than the 

 hand of the larger cheliped, but shorter than the carpus; palm oblong, 

 the margins parallel, the fingers not gaping; dactyl longer than the pollex 

 and not hooked at the tip. The smaller cheliped in the female is like that 

 of the male but the larger cheliped is relatively smaller and of a different 

 form; the ischium is like that of the smaller cheliped and the merus rmich 

 the same but stouter and furnished with a more prominent inferior tooth; 

 the carpus is similar in shape to that of the other cheliped but relatively 

 shorter, scarcely one-half longer than broad, and but little longer than the 

 merus; both surfaces convex, the margins not produced as in the male; 

 hand as wide as the carpus, palm longer than broad, with the margins 

 subparallel; fingers a little shorter than the palm; dactyl a little dilated 

 near the base and curved at the tip. Ischium and merus of the ambula- 

 tory legs fringed with long hairs below; hand ovate, ciliated, much com- 

 pressed, fingers longer than the palm. Caudal appendages distally trun- 

 cated. Telson scarcely shorter than the uropods and furnished with a 

 rounded emargination at the tip. 



Length of specimen, male, 61 mm.; length of larger cheliped, 50 mm.; 

 of small cheliped, 32 mm.; width of carpus of large cheliped, 13 mm.; 

 length of same, 155 mm.; length of hand to tip of dactyl, 10 mm.; of 

 merus, 12 mm.; of ischium, 10.5 mm.. Length of larger cheliped of a 

 female, 31 mm.; of smaller cheliped, 28 mm. 



California (Dana); Mutiny Bay, Alaska (Lockington); 

 Puget Sound (Stimpson); Shoalwater Bay (Cooper); 

 Bodega Bay! San Francisco Bay! Tomales Bay! Santa 

 Barbara! San Pedro! 



