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maxillipeds less broad, and the greater foot of the anterior pair 

 proportionably much longer, narrower, and less hairy. The car- 

 pus is shorter than the body of the hand, while in G. Cah'forni- 

 ensis it is longer. In the smaller hand the finger and thumb 

 are equal in length. In C. gigas, the hand is much shorter and 

 stouter than in either of the other species. C. longimana is 

 found abundantly in Puget Sound, whence specimens were sent 

 by Dr. Suckley. 



AsTACus NiGRESCENS. Margins of the rostrum nearly par- 

 allel, 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. GamhelUi, 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. It is common in the vicinity of San Francisco. 



AsTACUs Trowbridgii. a large species having a general 

 resemblance to A. lemusculus, Dana, from which it diflfers in its 

 much less prominent thoracic spines, the posterior pair of which 

 are here scarce perceptible. Rostrum broad, with smooth, nearly 

 parallel sides ; terminal spine rather short. Hands large and 

 broad, of a reddish olive color, darker than that of the body. 

 Length, five inches. Found in the Columbia River, above As- 

 toria, by Lieut. Trowbridge. 



AsTACUs Klamathensis. Thorax smooth above, rather con- 

 tracted in front. Rostrum subtriangular, but with the lateral teeth 

 sufficiently distinct, sides smooth, converging. Posterior pair of 

 thoracic spines obsolete. Hands small ; dentation of inferior 

 edge of arm slight. Lateral margins of abdominal segments 

 broadly rounded, scarcely at all angular. Color, bright yellowish 

 white ; hands tinted with bluish. Length, three inches. Found 

 in Klamath Lake, by Dr. Newberry. 



Pandalus Dan^. Thorax glabi'ous. Twelve spines on the 

 dorsal crest and rostrum, the posterior one being at about the 

 middle of the carapax. Rostrum smooth above toward the trifid 



