386 BULLETIN OF THE 



But the most important line beyond our immediate shores, con- 

 nected with the past history of the Gulf Stream, would be one from 

 Panama westward into the deepest waters of the Pacific ; for dredgings 

 in that direction may prove that the deep-sea fauna is identical on both 

 sides of the Isthmus, and that therefore, at a comparatively recent 

 epoch, the great equatorial current of the Atlantic extended without 

 serious obstructions over parts of Central America to the Pacific 

 Ocean. 



Cambridge, November 16, 1869. 



