COMPLETE HAIG : EASTERN PACIFIC PORCELLANIDAE 111 



carpus. Manus without a dorsal swelling, outer margin thin ; covered 

 with fine granules, and proximal outer portion covered with long plu- 

 mose hairs. Fingers covered with fine granules; gape with a short, 

 thick pubescence, not produced into a tuft. 



Walking legs smooth or punctate, covered with long, scattered non- 

 plumose setae and fringed with plumose hairs. Merus unarmed, that 

 of leg 3 not inflated. 



Material examined: See Table 3?). 



Measurements: Males, 2.8 to 13.4 mm; non-ovigerous females, 

 3.9 to 14.5 mm; ovigerous females, 5.6 to 7.9 mm. The type was re- 

 ported to measure 10 by 10 mm. 



Color: Ground color of carapace white. Dark tawny on front be- 

 coming lighter on branchial areas. Eyestalk white with a little color 

 under eye. Eye bright green. Antennae very pale russet. Chela white 

 with ochraceous tawny on merus and two blotches on carpus. Fingers 

 light russet with reddish purple tint. Tip of fixed finger white. Och- 

 raceous tawny on fifth leg, and lightly on ambulatory legs and dactyl. 

 Dactyl of walking legs white with blackish brown tip. Ventral side 

 white. (Petersen, of a live specimen from Isla Isabel, Mexico) 



Many preserved specimens show a distinct orange color on the 

 fingers. 



Ecology: The species was dredged once by the Velero III off 

 Isla Isabel, Mexico, in 10-15 fathoms, along with corallines and gor- 

 gonids. On another occasion it was cracked from coral heads taken in 

 1 fathom at Isla Espiritu Santo, Gulf of California. Glassell (1937) 

 reported it from coral heads taken by the Xaca in 2.5 fathoms. Ac- 

 cording to Glassell, it is usually found in the lower part of the inter- 

 tidal zone ; most of the Hancock material was taken under stones in 

 the littoral. 



Ovigerous females were collected in March. 



Remarks: Petrolisthes crenulatus is restricted to the Gulf of Cali- 

 fornia, with slight extensions to the offshore islands to the south and 

 to the southern portion of the west coast of Baja California. In the 

 southern part of its range it overlaps with its closest relative, P. ort- 

 manni Nobili. 



Range: Bahia de la Magdalena, Baja California; Gulf of Califor- 

 nia, from Isla Angel de la Guarda to Mazatlan; Isabel and Tres 

 Marias Islands. 



