172 ALLAN HANCOCK PACIFIC EXPEDITIONS VOL. 24 



specimens, also, the margin of the anterior carpal lobe appears serrate- 

 edged because of distinct granules along it, and the margin may be 

 notched to form two or three teeth; the granular longitudinal crests on 

 the carpus are usually much more distinct ; the tubercle at the base of the 

 pollex is occasionally obsolescent; the granules near the outer margin 

 of the manus tend to form irregular longitudinal rows; and there may 

 be only traces of the long hairs which cover the chelipeds of larger in- 

 dividuals. 



Material exam'med: See Table 53. 



Measurements: Males, 3.4 to 17.0 mm; non-ovigerous females, 3.4 

 to 14.6 mm; ovigerous females, 4.0 to 17.4 mm. The maximum lengths 

 are considerably greater than that given by Stimpson for one of the 

 type males, 0.43 inches ( = 10.9 mm) . 



Color: Specimens preserved in alcohol in the Hancock Foundation 

 collections are light orange, many of them showing spots and blotches 

 of darker orange on the carapace and chelipeds. 



Ecology: Pachycheles rudis is an almost strictly littoral species; in 

 the intertidal zone it has been found in various situations, such as 

 under stones, in roots of kelp, in sponge cavities, among rock oysters 

 and mussels, beneath sponge and tunicate beds, in the discarded bur- 

 rows of dead boring clams, on pilings, and in discarded shells of bar- 

 nacles. According to MacGinitie (1935), a male and female live together 

 in pairs. Occasional specimens have been taken to a depth of 16 fa- 

 thoms. The Velero III dredged it off Santa Rosa Island in 13-16 fathoms 

 from a rock and coralline substrate; T. A. Burch recovered it from 

 submerged pilings in a depth of 6.5 fathoms at Redondo Beach; he 

 Velero IV took it at Santa Catalina Island in 9-11 fathoms and at Bahia 

 de Colnett in 5-6 fathoms, with the bottom unrecorded in both cases. It 

 may be significant that all the recoveries in depths of 5-16 fathoms 

 were made in the southern part of its range. 



The Hancock Foundation collections include ovigerous females taken 

 in every month of the year except September. 



Relationships: This species appears to be most closely related to 

 P. stevensii Stimpson, 1858, which has been reported from Vladivostok, 

 the Kuril Islands, and the colder waters of Japan. P. stevensii lacks the 

 long plumose hairs which decorate the chelipeds of P. rudis; the an- 

 terior margin of the carpus is armed with three or more distinct teeth; 

 and the manus bears three longitudinal grooves and lacks a large tuber- 

 cle at the base of the pollex. 



