of the Pacific Shores of North America. 493 
Hab. California. My specimens were purchased in the 
market of San Francisco. 
Mus. Smithsonian. 
ASTACUS LENIUSCULUS. Dans. 
Astacus leniuseulus, Dana; U. S. Exploring Expedition, Crust. i. 524. 
PL XXXIIL ENL 
May be recognized by its well-developed thoracic spines, 
and light color. 
Hab. Columbia River, (Expl. Exped.;) Puget Sound, 
(Expl. Exped., and Dr. Suckley.) 
Mus. Expl. Exped.; Smithsonian. 
ASTACUS TROWBRIDGII. Stimpson, 
Astacus Trowbridgii, Srrwrsox ; Proc. Bost. Soc. Nat. Hist. vi. 87. 
This large species has a general resemblance to A. lenius- 
culus. It differs from that species in having much less 
prominent thoracic spines, the posterior pair of which is 
ere but little developed, even in adult specimens. The 
Tostrum is also somewhat shorter and broader than in the 
preceding Species, with smooth, nearly parallel sides; ter- 
minal tooth of moderate length ; antero-lateral teeth suffi- 
ciently prominent. Dorsal area broader than in A. Gambelii, 
but narrower than in A. leniusculus. Hands large, robust, 
*qual in size; surface rough; fingers spinulose. A promi- 
nent, sharp Spine on the superior edge of the brachium near 
Its extremity. 
This species is of a reddish-olive color in preserved speci- 
mens, probably much darker in life. The color of the chele 
“touch darker than that of the body. The dimensions of 
à male specimen are as follows ;— 
Length of body 2 gu c RU (ot — tr qi inches 
Breadth «c i : : : : s j : 0 « 
Length of rostrum Uer. i E 50 * 
u 
terminal tooth of rostrum . n ‘ JB. — 
4 
mu . . URBANO EO Iu 
Chet s — 0. 12.5 i“ 
