274 University of California Publications in Zoology [Vou 23 
Biological Survey of San Francisco Bay.—Henugrapsus nudus is 
a strictly littoral species, recorded only from the middle bay, doubtless 
because all shore collecting was confined to that section. Specimens 
from one to a dozen or more were obtained at Point Bonita, along the 
Presidio shore, at Sausalito, north of the Key Route pier, on Red 
Rock, and in tide pools along the Richmond shore, north of the 
Standard Oil pier. 
Hemigrapsus oregonensis (Dana) 
Plate 48 
Pseudograpsus oregonensis Dana, Proc. Acad. Nat. Sci. Phila., 5, 248, 1851; 
Crust. U. 8S. Expl. Exped., 1, 334, 1852, pl. 20, fig. 6, 1855. 
Heterograpsus nudus Rathbun, R., The Fisheries and Fishery Industries 
of the U. S., see. 1, p. 765, 1884. 
Brachynotus oregonensis Holmes, Occas. Papers Calif. Acad. Sci., 7, 82, 
1900. 
Hemigrapsus oregonensis Rathbun, H. A. E., 10, 189, 1900; Weymouth, 
Stanford Univ. Publ., Univ. Ser., no. 4, 63, pl. 14, fig. 43, 1910; Rath- 
bun, Bull. U. S. Nat. Mus., 97, 270, pl. 70, 1918. 
niet 
Fig. 162. Hemigrapsus oregonensis, outline of front, X 44 (after Dana). 
Characters.—Carapace more strongly undulated in front than in H. nudus, 
but not so much flattened behind; posterior portion not punctate, and anterior 
portion may be sparsely granulate; front with a.deep sinus in the middle, front 
four-lobed, the median lobes the most prominent. Chelipeds smooth, not spotted 
with red; in the adult male there is a rounded lobe on the antero-internal angle 
of the merus, and a patch of long hair on the inner surface of the hand. Ambula- 
tory legs hairy; dactyls narrower than in H. nudus, those of the last pair 
upturned. 
Dimensions.—Type: length of carapace 21.2 mm., width 24.4 mm. The Bay 
specimens ranged from 3 to 29 mm. in width of carapace, the greater number being 
about 20 mm. wide. 
Color.—In life a light grey, with minute blackish or dark blue spots, which 
are more numerous in some regions than in others. Legs lighter, marked with 
similar spots; hands of chelipeds whitish in tone, without spots (Weymouth). 
Type Locality —Puget Sound. 
Distribution—From Prince William Sound, Alaska, to Gulf of California 
(Rathbun). 
Remarks.—This species may be readily distinguished from the preceding by 
its dull color, hairiness of the legs, the four-lobed front, and absence of round 
red spots on the chelipeds so characteristic of that closely related species 
(Holmes). 
