of the Galapagos Archipelago. 255 



mentioned by Colnett as being' drifted on the south-east coasts of the Galapa- 

 gos, are perhaps, though remotely, due ; and to its agency may be ascribed 

 the introduction of the following littoral Peruvian and Chilian plants : — 



Vigna Owyhensis. Lycopersicum Peruanum et pimpinellifolium esculentum. 



Acacia Cavenia. Verbena littoralis. 



Nicotiana glutinosa. polystachya. 



Dictyocalyx Miersii. Plantago tomentosa. 



Had this body of water flowed along more fertile coasts than the desert 

 shores of Peru, or received any large rivers in its course, the Flora of the 

 Galapagos might have presented a very different appearance. On the other 

 hand, let it be borne in mind, that the sterility of the coasts of this archipelago 

 is peculiarly unfitted to the propagation of any but the most vigorous weeds 

 of the tropics ; had it been otherwise, it cannot be doubted that the palms, 

 canes and bamboos (which are probably originally from the Guayaquil river, 

 and taken up by the north edge only of this current,) would have vegetated 

 here as well as in Cocos Island, only 300 miles to the north, whose vegetation 

 is of tropical luxuriance*. 



Another current, that by which the West Indian plants are probably intro- 

 duced, is one which, though not laid down in any chart, appears from the 

 observations of Captain Fitzroy to flow from the Bay of Panama, on the north- 

 east of the Galapagos, and mingle its waters with the polar current ; its ori- 

 gin is in the heated waters of that gulf; and the evidence of its visiting the 

 Galapagos rests not only on the presence of so many species of plants, but on 

 the fact, that the currents which wash the shores of the northern islands of the 

 group are sometimes 10 degrees warmer than the south polar current at the 

 southern islands ; whilst the intervening space is far too narrow to admit of 

 the supposition that the difference is owing to local causes. This current is 

 doubtless a very partial one, but its effect is powerful, rendering the climate of 

 one part of the group very different from that of the other, — a difference which 

 is accompanied by certain changes in the vegetation. 



There is one other point demanding attention, which relates to the crossing 



* The presence of this current is of the highest importance in eflFecting the distribution of antarctic 

 Algse, for its cold waters are the means of carrying far into the tropics of this meridian, species which 

 in other longitudes are entirely confined to very high latitudes. 



