76 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



a thick pubescence produced on proximal half of fingers into a long 

 tuft. 



Walking legs granular; merus unarmed, that of leg 3 not inflated; 

 merus and carpus covered with plumose and non-plumose hairs, pro- 

 podus and dactylus with long tufts of hairs. 



Material examined: See Table 19. 



Measurements: Males, 4.4 to 15.1 mm; non-ovigerous females, 3.8 

 to 15.0 mm; ovigerous females, 3.9 to 12.6 mm. The size of the type 

 specimen was not recorded. 



Color: Reddish brown mottled with varying amounts of blue . . . 

 At least part of outer maxilliped and proximal internal angle of dactylus 

 of cheliped a bright porcelain blue. (Hart, 1930) 



Ecology: In general, Petrolisthes eriomerus occurs under stones in 

 the lower part of the tidal zone from the northern part of its range 

 south to San Luis Obispo County, California. It has occasionally been 

 taken from submerged jetties, eelgrass roots, and kelp holdfasts. Way 

 (1917) reported it from 25 fathoms at Friday Harbor, Washington. 

 Glassell's (1945) record for the northern Santa Barbara Islands does 

 not specify depth of capture, but the Velero III and IV dredged it in 

 that area at a depth of 5 to 30 fathoms, and the Velero III took it off 

 Anacapa Island in 45-47 fathoms (substrates of rock, gravel, sand, and 

 shell). The only mainland record south of San Luis Obispo County is 

 La Jolla, where it was collected from kelp beds, probably also at sev- 

 eral fathoms' depth. P. eriomerus is often found associated with 

 Pachycheles pubescens Holmes, which like it characteristically inhabits 

 the intertidal zone from British Columbia to San Luis Obispo County, 

 California, and deeper water off the Channel Islands and the mainland 

 to the south. 



Remarks: Female and juvenile specimens of Petrolisthes manima- 

 culis Glassell, with rough granules on the anterior regions of the cara- 

 pace and on the carpus of the chelipeds, often resemble P. eriomerus 

 very closely. The two species may always be distinguished by the length- 

 width ratio of the carpus. In P. manimaculis the length of the carpus is 

 not less than 2.4 times the width; in P. eriomerus it seldom exceeds 

 two times the width, and is never as much as 2.4 times. 



Range: Queen Charlotte Islands, British Columbia, south to La 

 Jolla, California ; off Santa Barbara Islands. Shore to 47 fathoms. 



