254 Dr. J. D. Hooger on the Vegetation 
the very considerable number of widely diffused plants which are admirably 
adapted for availing themselves of this means of transport; though, on the 
other hand, the exquisite care with which sea-fowl plume themselves must 
not be overlooked, nor the slender chance there is of a seed remaining attached 
to a body subjected to such violent motion and constant immersion as these 
birds undergo. The plants which may have been thus introduced are species 
of Tribulus, Siegesbeckia, Nicotiana, Dicliptera, Plumbago, Pisonia, Boerhaavia, 
Poa ciliaris and Setaria Rottleri: all belonging to this section are ubiquitous 
plants throughout the tropics. 
As no land-bird is common to the Galapagos and mainland of America, 
this group is deprived of one very frequent means of transport,—the stomachs 
of birds, which often receive seeds as the food, especially of the migratory 
species ; these pass undigested from them in a locality far removed from 
that where they were collected, not only with unimpaired vitality, but with 
the process of germination accelerated. 
Man is the last agent to which I alluded: that he has been already active 
is very perceptible from the fact, that Charles Island, the only colonized island, 
contains the smallest proportion of peculiar plants, and numerically far the most 
of these common to and probably introduced from the coast with cultivation. 
If the non-peculiar plants of the Galapagos then have been introduced from 
the continent of America, it is the currents and winds that we must regard as 
the agents; of these, the winds are steady south-east trades, blowing from the 
coast of Peru, by which the West Indian species cannot have been carried. 
The currents are more variable; and to these I would direct attention, and 
have brought together all the information on this subject I could command, 
from the voyages of the English and French in the seas between the Gala- 
pagos and American shores. 
The principal oceanic current is a branch of the Antarctic or Southern Polar ; 
it is a large body of cold water, which flows northwards from the icy regions to 
the equator, parallel to, or perhaps impinging on the west coast of South Ame- 
