1921] Schmitt: The Marine Decapod Crustacea of California 273 
Hemigrapsus nudus (Dana) 
Plate 47 
Pseudograpsus nudus Dana, Proce. Acad. Nat. Sci. Phila., 5, 249, 1851; 
Crust. U. S. Expl. Exped., 1, 335, 1852, pl. 20, fig. 7, 1855. 
Heterograpsus nudus Rathbun, R., The Fisheries and Fishery Industries of 
the U. S., see. 1, p. 765, 1884. 
Brachynotus nudus Holmes, Oceas. Papers Calif. Acad. Sci., 7, 81, 1900. 
Hemigrapsus nudus Rathbun, H. A. E., 10, 189, 1904; Weymouth, Stanford 
Univ. Publ., Univ. Ser., no. 4, 62, pl. 14, fig. 42, 1910; Rathbun, Bull. 
U.S: Nat.) Mus? 97,267, pli 69; 191s: 
Fig. 161. Hemigrapsus nudus, X % (after Dana). 
Characters.—Carapace posteriorly flat, smooth, and punctate, anteriorly con- 
vex, undulated, and furnished with small, scattered granules; front arcuate, 
very slightly sinuous (front bilobed, median emargination shallow but compara- 
tively broad). Chelipeds smooth, mottled above with small, round, red spots; 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. Ambulatory legs 
naked, rather short; dactyls short, stout, scabrous, those of last pair less than 
two and one-half times, often less than twice as long as wide, and up-turned 
at the tip. 
Dimensions.—Type, female: length of carapace 22.3 mm., width 26.5 mm.; 
male: length of carapace 22.6 mm., width 26.1 mm. Width of carapace of the 
Bay specimens ranged from 9 to 39 mm., the greater number being about 25 mm. 
wide. 
Color.—Quite variable. It is generally of a mahogany red, but may be a 
purplish tone, dark red, or red marbled with white. I have seen some specimens 
with the upper side almost entirely white (Holmes). Ambulatory legs similar to 
carapace; chelipeds lighter, marked with numerous small spots of darker red 
(Weymouth). But amid all the variations of color the red spots on the chelipeds 
remain an absolutely constant character so far as I can determine. Young speci- 
mens present greater color variation than older ones (Holmes). 
Type Locality—Puget Sound. 
Distribution—From Sitka, Alaska, to Gulf of California (Rathbun). 
