166 CALIFORNIA ACADEMY OF SCIENCES. 



Astacus leniusculus Dana. 



Astacus leniusculus DANA, Proc. Acad. Nat. Sci. Phila., 1852, p. 20; Crust. 

 U. 8. Expl. Expd., Part I, 1852, p. 524, PI. XXXIII, fig. 1. STIMPSON, 

 Journ. Bost. Soc. Nat. Hist., Vol. VI, 1857, p. 493. HAGEN, 111. Cat. 

 Mus. Comp. Zool. Harvard Coll., No. 3, 1870, p. 94. LOCKINGTON, 

 Ann. Nat. Hist. (5), Vol. II, 1878, p. 304. FAXON, Proc. Amer. Acad. 

 Arts and Sci., Vol. XX, 1884, p. 151; Mem. Mus. Comp. Zool. Harvard 

 Coll., Vol. X, No. 4, 1885, p. 132, PI. VI, fig. 4; Proc. U. S. Nat. Mus., 

 Vol. VIII, 1886, p. 356. Ibid., Vol. XX, 1898, p. 666. 



Closely allied to Troicbridgii. Carapace punctate. Kostrum trispi- 

 nose, the median spine long and slender; tiro pairs of spines at the base. 

 Cardiac area rather wide. Carpus of the chelipeds unarmed with the 

 exception of the antero-internal angle; merus denticulated and armed 

 with a dorsal spine . 



Length, 4 inches. 



Columbia River (Dana); San Francisco County, 

 Calif. (Faxon). 



Astacus nigrescens St. 



Astacus nigrescent STIMPSON, Proc. Bost. Soc. Nat. Hist., Vol. VI, 1857, 

 p. 87; Journ. Bost. Soc. Nat. Hist., Vol. VI, 1857, p. 492. HAGEN, 

 HI. Cat. Mus. Comp. Zool. Harvard Coll., No. 3, 1870, p. 92, PI. III. 

 LOCKINGTON, Ann. Nat. Hist. (5), Vol. II, 1878, p. 303. HUXLEY, The 

 Crayfish, p. 244, fig. 62. FAXON, Proc. Amer. Acad. Arts and Sci., 

 Vol. XX, 1884, p. 152; Mem. Mus. Comp. Zool. Harvard Coll., Vol. X, 

 No. 4, 1885, p. 135; Proc. U. S. Nat. Mus., Vol. VIII, 1886, p. 356; 

 Ibid., Vol. XII, 1890, p. 634. 



" Margins of the rostrum nearly parallel, denticulated with five or six 

 small sharp spines on either side; the two anterior thoracic spines rather 

 long. Dorsal area between the branchial regions as wide as in A . Gambellii, 

 from which this species differs in its smaller and more slender hands, which 

 are also without pubescence. The lateral angles of the abdominal segments 

 are sharp, and the caudal segment has two slender spines on each side. 



Color, blackish. 



Length three inches." 



Unalaska, Alaska; Fort Steilacoom, Washington; 

 San Joaquin Slough, Coyote Creek, Santa Clara County; 

 Alameda Creek, Alameda County, California (Faxon). 



