32 G'eographical Distribution of Crustacea. 
* Libinia, in the same. manner, has its species on the Atlantic 
and Pacific coast of the United States, and the coasts of Western 
and Eastern South America. —Mithraz is as widely distributed. 
Epialtus oceurs in. the West Indies, California, Brazil, Galla- 
pagos, and. Valparaiso. Potamia has two West Indian and one 
Ch'lian species. 
Eurypodius of Southern South America has its representative * 
at Puget's Sound, in the genus Orezonia. 
Again, the Libinia dubia of. the West Indies, is hardly distin- 
guishable, according to Prof. L. R. Gibbes, from the £L. affinis, - 
Baud. df the California coast. LL. spinosa, of Brazil, is also... 
found in Chili. .Leptopodia sagittaria occurs in the West Indies, 
and also, according to Bell, at Valparaiso; Acanthonyz Petiverii (). 
in the West Indies, Prazil, and Gallapagos; AZpialtus margi- 
natus, on the coast of Brazil and at the Gallapagos (Bell); Epi- | 
altus bituberculatus, in Chili, and at Key West; Uca una, Guay- 
aquil and West Indies ; Albunea 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 bani E 
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. "'lhey are mostly Maioids; the large 
group of the Caneroids, which belong mainly to warm waters, 
does not include a single genus exclusively American, and of the 
family Leucosidz, of the Leucosoids, there are only three known 
species. 
We also perceive why the western coast of America has no. 
zoological affinity with the Pacifie Islands. .. 'l'he 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. 'l'he two kingdoms are 
widely different in most respects. 
In the first place, the genera Lupa, Gelasimus, Ocypoda, 
Libinia, Epialtus, Hepatus, well represented on the American 
coasts, are not known on the European, besides others ('l'able 1, 
on a preceding page) of less prominence. 
Again, therecare several genera common in Europe, not known 
in America, as Znachus, Maia, Acheus, Portunus, Ebalia, La- 
treillia, Athanas, in addition to those included in 'T'able 2. . 
Still, the American and. Áfrico-European kingdoms have a 
common character separating them from the Oriental. . F'or ex- 
ample: the great genus Cancer occurs in both of these kingdoms, 
