I 78 RATHBUN 



CANCER OREGONENSIS (Dana). 

 Plate vn, fig. i. 



Trichocera oregonensis DANA, Proc. Acad. Nat. Sci. Phila., vi, 86, 1852; 



Crust. U. S. Expl. Exped., I, 299, 1852, pi. xvm, fig. 5, 1855. 

 Platycarcinus recurvidens BATE, Proc. Zool. Soc. London, 1864, 663. 

 Trichocarcinus oregonensis MIERS, Proc. Zool. Soc. London, 1879, 34- 



HOLMES, Occas. Papers Calif. Acad. Sci., vn, 54, 1900, and synonymy. 

 Trichocarcinus recurvidens WALKER, Trans. Liverpool Biol. Soc., xn, 271, 



pi. xv, figs, i-ib, 1898. 

 Trichocarcinus Walkeri HOLMES, op. cit., 53. 



Harriman Expedition. Fox Island (Kincaid); Virgin Bay (Coe); 

 Orca; Yakutat; Sitka. 



Distribution. Aleutian Islands to Lower California (Holmes). Low 

 water to 238 fathoms. 



I am unable to separate from typical C. oregonensis the form described 

 by Walker under the specific name recurvidens, and later by Holmes as 

 Trichocarcinus walkeri, because the species displays more variation and 

 intergradation than was known to those authors. Material from 43 

 localities has been examined. In a lot of specimens collected by Dr. 

 Dall at Coal Harbor, Unga Island, Alaska, are not only typical oregonensis 

 and typical walkeri, but some with sculpturing and teeth intermediate 

 between the two ; others more deeply areolated than in typical walkeri, 

 but with teeth as narrow and well separated as in the other extreme of 

 oregonensis. In a lot of fairly typical oregonensis from the Strait of Fuca 

 (D. S. Jordan) is one in which many of the granules of the areolae 

 are prolonged into conical spines. Still another variation is shown 

 by a single male (plate vn, fig. i) from station 3274 (Albatross], 

 northeast of Amak Island, Alaska, 19 fathoms, where the lateral teeth 

 are broader and more overlapping than in the specimen figured by 

 Walker (loc. cit.} ; the granulate areolse are small, round, and raspberry- 

 like, the interspaces much smoother than usual. 



Size. The largest specimen measured is a female from Puget Sound 

 (O. B. Johnson), 36.5 mm. long, 47.1 mm. wide. 



Cancer oregonensis might well be set apart genetically on account of 

 the antero-lateral margins not being sharply marked off from the postero- 

 lateral, in which respect it differs from the other species of Cancer, in- 

 cluding C. gibbosulus and C. amphioetus. The name Trichocarcinus is 

 not, however, available for the species oregonensis, as the type of Tricho- 

 carcinus Miers, substituted for Trichocera de Haan, preoccupied, is Cancer 

 gibbosulus (de Haan). This species I consider a true Cancer (see p. 176) ; 

 therefore Trichocarcinus is a synonym of Cancer. 



