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Geographical Distribution of Crustacea. 177 
Eibinia, in the same manner, has its species on the Atlantic 
and Pacific coast of the United States, and the coasts of Western 
aud Eastern South America. Mithrar is as widely distributed. 
Epialius occurs in the West Indies, California, Brazil, Galla- 
pagos, and Valparaiso. Potamia has two West Indian and one 
Chilian species. 
Elurypedius of Southern South America has its representative 
at Puget’s Sound, in the genus Oregonia. 
Again, the Libinia dubia of the West Indies, is hardly distin- 
guishable, according to Prof. L. R. Gibbes, from the ZL. affnis, 
Rand., of the California coast. JZ. spinosa of Brazil, is also 
found in Chili. Leptopodia sagittaria occurs in the West Indies, 
and also, according to Bell, at Valparaiso; Acanthonyx Petiverii(?), 
inthe West Indies, Brazil, and Gallapagos; E/pialtus margi- 
natus, on the coast of Brazil and at the Gallapagos (Bell); E’pz- 
altus bituberculatus, in Chili, and at}Key West; Uca wna, Guay- 
aquil and West Indies; Albun@a scutellata, West Indies and 
San Lorenzo, Peru; Hippa emerita and talpoides, both on East 
and West America, North and South. 
It is obvious, therefore, that the east and west sides of America 
are very closely related, and differ widely in a zoological sense, 
from either of the other kingdoms. 
_ We observe further, that nearly all the genera peculiar to Amer- 
ica are cold-water genera. They are mostly Maioids; the large 
group of the Cancroids, which belong mainly to warm waters, 
does not include a single genus exclusively American, and of the 
family Leucoside, of the Leucosoids, there are only three known 
Species. 
We also perceive why the western coast of America has no 
_ Zoological affinity with the Pacific Islands. The temperature of 
their waters is widely different ; and, moreover, the oceanic cur- 
rents of the tropics run from the American coast to tbe west- — 
ward, and are a barrier to migration eastward. 
The relations of the American or Occidental to the Africo-Eu- 
ropean kingdom are of much interest. The two kingdoms are 
Widely different in most respects. 
ce 
gain, there are several genera common in Europe, not known 
in America, as Inachus, Maia, Acheus, Portunus, Ebalia, La- 
treillia, Athanas, in addition to those included in Table 2. 
ample: the great genus Cancer occurs in both of these kingdoms, 
Szconp Sznizs, Vol, XX, No. 59.—Sept., 1855. 23 
