INTRODUCTION OF FOREIGN SPECIES. 153 
principal stream and the currents originating in it, bear 
upon their surface various vegetable and other produc- 
tions brought by rivers into the Gulf, or swept from ita 
shores, and these are frequently deposited upon parts of 
the coast very distant from their origin. In this way 
seed-vessels from the Spanish Main, trunks of trees and 
fragments of wood of unascertained origin, and numer- 
ous objects from the northern shore of Cuba, are fre- 
quently found on the shore of Key West, and on the 
beach of Cape Florida and the shores and islands to the 
north of it.' These circumstances are adequate to 
account for the transmission of land-shells from the 
Island of Cuba, and even from more distant places, to 
the main land and islands of Florida ; and to this source 
we ascribe the origin of Helix rJwdocheila, and Byliwm 
virgulatus, which are probably derived from the Ba- 
hamas, but possibly from the Spanish Main, and of 
Helix ottonis, Bulimus fasciatus, B. zebra, B. subula. 
Pupa incana, Cyclostoma dentatum, and Cylindrella 
lactaria, all undoubtedly from Cuba, which, having 
found a congenial soil and climate in the southern 
part of the peninsula of Florida, are now flourishing 
there in great numbers. To the same cause may 
1 A few years since a bottle was picked up on Tavernia Key, near Cape 
Florida, containing a note stating that it was thrown overboard off the Moro 
Castle. A Cuba barge, of the kind used in lading and unlading vessels in 
Matanzas, was lately found stranded on the beach at New River, twenty- 
five miles north of Cape Florida. Small objects from Cuba are often found 
on the shore of Key West. 
vol. I. 40 
