DESCRIPTIONS OF NEW DECAPOD CRUSTACEANS FROM 
THE WEST COAST OF NORTH AMERICA. 
By Mary J. Rathbun, 
Second Assistant Curator, Dhisiov of Marhie Invertebrates. 
The species and subspecies here described are the result chiefl}^ of a 
stud}^ of the vast collection of shrimps from the coast of Alaska south- 
ward to San Dieg'o, California, which have been accunuilating for 
manv years in the United States National Museum, and have been 
obtained largely by the United States Fish Commission steamer 
AJhatr(>s.'<. Besides the shrimps, one new crab, an Oregonia^ was 
dredged l)y the Alhatro-s.s during her cruise in Bering Sea in 1900. 
In connection with the publication of the Decapod Crustacea of the 
Hai'riman Expedition, it is proposed to g'ive a list of the forms known 
to inha])it the coast of western America (north of Mexico) and to 
more fuU}^ describe and figure the new and little-known species. 
Family MAIID^. 
OREGONIA BIFURCA. 
Surface tuberculate and hairy. Postorbital width two-thirds of 
branchial width. Rostral horns divergent from their base. Basal 
joint of antenna armed on its outer edge with a stout blunt subter- 
minal spine and three small spines, one of which is at the anterior 
angle. Inner surface of merus of chelipeds bordered by short blunt 
spines; propodus slightly longer than merus, fingers and palm sub- 
equal, margins of palm subparallel, Dactyli of ambulatory legs con- 
tained about one and a third times in their propodi. 
Dhiiensions. — Length of carapace and rostrum 26.. 5 mm., width of 
carapace 10.6 mm., width between tips of postorbital spines 13 mm., 
length of horn measured along the inner edge 3.1 mm., distance 
between tips of horns 3.. 5 mm. 
Type locality. — One specimen onh', a female, was taken ))}' the U. S. 
Fish Commission steamer AJhatr'oss at station 3785, north of Rat 
Islands, Aleutians, 270 fathoms (Cat. No. 25287). 
Proceedings U. S. Natiomal Museum. Vol. XXIV— No. 1272. 
885 
