AMERICAN AND WEST INDIAN FAUNA AND FLORA. 117 



have acted upon oceanic islands. The proximity of these islands 

 to a great continent has, however, intensified the efficiency of 

 these causes. 



Among the oceanic islands which show most clearly the effects 

 of ocean currents and of winds on the distribution both of ma- 

 rine and of terrestrial animals and plants, the Bermudas are 

 the most interesting. Situated in the very track of the Gulf 

 Stream, we readily trace to their origin a host of littoral marine 

 animals and many plants, known to us from the investigations 

 of the older naturalists, in the West Indies and the northern 

 shores of South America ; while the more recent investioations 

 have shown the community of origin of a number of rarer Ber- 

 mudan types with forms found in the deeper waters of the Ca- 

 ribbean Sea, the young of which are carried northward during 

 their pelagic embryonic stages, wdth the seeds of many of the 

 plants which have become acclimated in the Bermudas. 



The fact that the Bermudas are of comparatively recent ori- 

 gin shows how varied the fauna and flora of a group may 

 become when placed in the path of a current or of prevailing 

 winds, and how comparatively little time is required for the 

 acquisition of faunistic characters which may closely link the 

 group to distant shores. Were the conditions of winds and 

 currents changed, we might be tempted to explain these charac- 

 ters upon the theory of former land connections, which perhaps 

 never existed. 



The vegetation of the Bermudas is thoroughly Floridian and 

 West Indian, consisting of palmettos, mangroves, junipers, limes, 

 etc. ; and we can easily see how the seeds or shoots of many 

 plants can have been brought by the Gulf Stream and settled on 

 the low shores of the islands when they once rose above the level 

 of the sea. There are no mammals except the rats and mice 

 imported with vessels. The birds are not numerous ; they are 

 common North American species, of which only a few breed 

 on the island, while there are other annual visitants. The 

 only land reptile known there is closely allied to, if not iden- 

 tical with, a species of skink inhabiting the Carolinas, and the 

 marine fauna and flora are West Indian. The large turtles of 

 the coast of Florida, the fishes, mollusks, Crustacea, polyps, and 



