PART 1 GARTH : PACIFIC OXYRHYNCHA 201 



Chelipeds strong; merus with a prominent thin and irregular carina 

 on margins ; carpus strongly carinate above and on inner margin, outer 

 and upper surfaces irregularly ridged ; hand large, compressed, margins 

 thin; palm nearly as broad as long; fingers gaping, a tooth near base of 

 dactyl, and one on pollex toward distal end of gape. 



Legs much more slender than in Pugettia richi of equal size; first 

 pair about as long as, or longer than the chelipeds ; three succeeding pairs 

 short, decreasing regularly in length ; margins fringed with club-shaped 

 setae. 



Females differing from adult males in having a broader and more 

 ovate carapace, three distinct branchial areolations, when the pubescence 

 is removed, and a much more swollen gastric region. (Rathbun, 1925, 

 modified) 



Material examined: 297 specimens from 85 stations. (See Table 36) 

 From San Miguel Island, California, to Thurloe Head (Thurloe Bay), 

 Lower California, Mexico, including all important offshore islands ex- 

 cepting Guadalupe. 



Measurements: Largest specimen, a male: length 18.0 mm, branchial 

 width 13.8 mm, hepatic width (including spine) 11.2 mm, rostrum 5.2 

 mm, basal width 2.9 mm, cheliped 21.6 mm, chela 11.2 mm, dactyl 5.75 

 mm, ambulatory legs 22.5, 16.0, 12.5, and 12.5 mm, respectively. Oviger- 

 ous female: length 14.6 mm, branchial width 10.3 mm, hepatic width 

 9.1 mm. 



Color in life: Unrecorded, but varying with their algal surroundings. 



Habitat: Taken at Corona del Mar from eel grass beds, and at Santa 

 Catalina Island from Eisenia holdfasts and from clumps of Lithothrix 

 and Liagora. Dredged specimens frequently had pieces of a calcareous 

 alga attached, and specimens from Santa Cruz Island and South Bay, 

 Cedros Island, supported colonies of a bryozoan identified by R. C. Os- 

 burn as Holoporella brunnea (Hincks). 



Depth: Intertidal to 64 fathoms. 



Size and sex: An exceptionally fine series was obtained from kelp 

 holdfasts (Eisenia) and from clumps of Lithothrix and Liagora at White 

 Cove, Santa Catalina Island, station 1378-41. In it were found males of 

 from 4.0 to 8.0 mm, females from 4.5 to 6.5 mm, ovigerous females from 

 6.0 to 6.5 mm, and young to a minimum of 2.0 mm, the latter but little 

 larger than a megalops present in the same series. Although the dimen- 

 sions of the 40 individuals were well under the average of specimens 

 living outside the kelp holdfast community, their gradation was so per- 

 fect that no essential stage was omitted. 



