496 Stimpson on the Crustacea and Echinodermata 
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.) i 
Mus. Bost. Soc.; Phil Acad.; Smithsonian; Paris; 
Acad. Petrop. 
CRANGON NIGRICAUDA. Stimpson. 
Plate XXII. f. 6. 
Crangon vulgaris, Owen, (non Farr.) Zool. of Beechey's Voyage, p-87- exe 
U. S. Exploring Expedition, Crust. i. 536, ii. 561 
Crangon nigricauda, Stimpson ; Proc. Cal. Acad. Nat. Sci. 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 pol? 
caudal segment, which has also a shallow longitudinal P 
row along the upper surface. The antepenultimate abor 
