Shallo 
of many Mollusca, Crustacea, and Fishes, but not the 
PROCEEDINGS OF SCIENTIFIC SOCIETIES. 503 
Species, but its principal influence is indirect, by influencing tempera- 
animals to extend in deep water farther toward the equator than upon 
the shore. The number of species of each class of Radiates found in the 
Several provinces was stated, together with those that were peculiar 
sou Th 
coasts of America and Europe, and, in some cases, upon the 
Pacific coast of Asia; several of the common New England Star-fishes, 
Sea-urchins, and Actiniæ are examples of species having this wide 
O the latter being common e Tropical or Panamian province, 
extending from the head of the ide of California and Cape St. Lucas 
to Cape Blanco, Peru, was compared with the Caribbean province, 
extending on the Atlantic pri from Florida to Brazil, ahd including 
the West Indian Islands. Very few species of Radiates are recorded 
as identical between the Atlantic and Paciñc, and these are all Holo- 
thurians, and therefore doubtful. The Polyps and Corals are remark- 
vin 
n to those ofthe Atlantic. All the evidence is against the suppo- 
hmus, since the 
more evidence of existing 
ific species passing into the Atlantic, than the contrary. 
In conclusion, it was thought that a depression of about three 
red feet, causing a connection across the Isthmus by means of a 
w estuary of brackish’ water, sufficiently pure to sustain the life 
floating germs 
of of Corals and other Radiates, would: waticieaty account for the distri- 
ut to account for the distinct 
In- 
“open species belonging often to genera not found in the East 
