56 Crustacea and Echinodermata of the 



large, (see figure,) with an oblique palm, more nearly lon- 

 gitudinal than transverse, occupying nearly one third of 

 the length of its inner side ; thumb-like process long and 

 spiniform. Sternal spine long, and followed by two or 

 three sharp tubercles on the succeeding thoracic segments. 

 A small sharp spine on each side of the abdomen at the 

 supero-lateral angle of the antepenultimate segment. Cau- 

 dal segment long, slender, and pointed, smoothly rounded 

 above. Color light and dark yellowish-gray, mottled. Eyes 

 salmon-colored in life. Length about three inches. 



The peculiar character of the hand in this species will 

 enable it to be readily distinguished from all others. 



This is the common shrimp of the San Francisco market. 

 It is found very abundantly in the sandy coves around the 

 Bay, is perhaps the most valuable crustacean of this coast, 

 for besides being used as food, it is the common, and almost 

 the only bait with which fish of all kinds are taken. 



Among other localities in which this species has been 

 found, the following may be mentioned : Puget Sound, 

 (Suckley ;) Shoalwater Bay, (Cooper ;) Tomales Bay, (Sam- 

 uels ;) and Monterey, (Taylor.) 



Mus. Bost. Soc. ; Phil. Acad. ; Smithsonian ; Paris ; 

 Acad. Petrop. 



CRANGON NIGRICAUDA. Stimpson. 



Plate XXII. f. G. 



Crangon vulgaris, Owen, (non Fahk.) ZhoI. o/Beechey's Voyage, p. 87. Dana, 



/ . S. Exploring Expedition, Crust, i. 5.36, ii. 561. 

 Crangon nigricauda, Stimpson ; Pruc. Col. Acad. Nat. Sri. i. 89. 



This species resembles very closely the common shrimp 

 of Europe and of the Northern United States. It differs, 

 however, from that species in its broader carapax, its slightly 

 smaller, and comparatively shorter hand, and more pointed 

 caudal segment, which has also a shallow longitudinal fur- 

 row along the upper surface. The antepenultimate abdom- 



