458 PROCEEDINGS OF THE NATIONAL MUSEUM vol. u5 



were a uniform white or yellow in the light but became pink or orange 

 in the dark. The change in color is due to the presence of tiny red 

 chromatophores thicldy dotted over the dorsal half of the animal 

 (except over the eyes) and on the chelae. These expand in the dark. 

 In some specimens there is a pale blue tinge to the chelae and the 

 flagella. The cast skin is a very pale blue dorsally, with yellow setae 

 on the antennal blade and on the tail fan. The chitinous tips of the 

 dactyli of the legs are yellow. 



Size. — Carapace length of smallest ovigerous female 4.8 mm.; 

 largest female 8.5 mm.; males 3-7 mm. Length of chela of largest 

 female 9 mm.; of largest male 9 mm. 



Range. — Morro Bay, Calif., to Hecate Strait, Queen Charlotte 

 Islands, British Coliunbia. 



Habitat. — The ''B. harfof^di" fomid under a rock at low tide 

 (Holmes, 1900), under rocks and among seaweed (MacGinitie and 

 MacGinitie, 1949), and on pilings (Ricketts and Calvin, 1952), were 

 probably Betaeus setosus. The one specimen taken in Washington 

 was found intertidally under a rock on the exposed west side of San 

 Juan Island. In British Columbia, one specimen was dredged at 

 10 fathoms, some were found in tide pools, and others with Pachy- 

 cheles rudis Stimpson in cavities mider the holdfasts of kelp (usually 

 Pterygophora californica Euprecht) or eelgrass roots (Phyllospadix 

 species). They often occur in pairs. 



Material. — The following specimens were examined: 



California. — Morro Bay, under rocks, Feb. 1, 1939, S. A. Glassell, 2 ovigerous 

 females. — Monterey Bay, China Point, shore, June 1908, 2 males (Hopkins 

 Marine Station). — Monterey Bay, HMS Line Sui-vey, No. 86, June 2, 1931, 

 G. E. MacGinitie, 2 males (Hopkins Marine Station). — Monterey Bay, J. C. 

 Brown, 1 ovigerous female, 1 male (USNM 23932). — Tomales Point, Dec. 26, 

 1939, E. F. Ricketts, 2 males. — Tomales Point, reef, Laviinaria, June 9, 1948, 

 1 female, 1 male (Pacific Marine Station). — Tomales Point, ocean side, Nov. 28, 

 1947, 1 female, 1 male (Pacific Marine Station). — Campbell's Cove, inside en- 

 trance to Bodego Lagoon, Feb. 11, 1949, Lee O. Miles, 1 ovigerous female (Pacific 

 Marine Station).- — Dillon Beach, rocks, north, June 30, 1946, 1 ovigerous female 

 (Pacific Marine Station). 



Washington. — San Juan Island, west side, under rocks, intertidal, July 10, 

 1960, P. L. lUg, 1 male. 



British Columbia. — Vancouver Island, west coast: Clayoquot Sound, Frank 

 Island, Cox Bay, Tofino, July 10, 1960, J. F. L. Carl, 3 ovigerous females, 1 male; 

 Clayoquot Sound, July 29, 1961, J. F. L. Carl, 1 female holotype (USNM 108229), 

 5 females (3 ovigerous), 3 males; Clayoquot Sound, Round Island, June 30, 1945. 

 E. F. Ricketts, 2 ovigerous females (USNM 80630); Clayoquot Sound, May 30, 

 1946, E. F. Ricketts, 1 ovigerous female, 1 male (USNM 84395); Clayoquot 

 Sound, Deadman's Island, June 27, 1945, E. F. Ricketts, 1 ovigerous female, 

 1 male (USNM 80635); Esperanza Inlet, High Island, near Catala Island and 

 Tatchu Point, June 28, 1934, E. G. Hart, 2 females (1 ovigerous), 1 male; Esper- 

 anza Inlet, Nootka Island, tide pool, July 25, 1934, E. G. Hart, 2 ovigerous fe- 



