50 GEOGKAPHICAL DISTRIBUTION. 



quent visits from the specific congeners on the mainland. Not 

 only are, with the one or two exceptions above noted, all the 

 Galapagos land-birds specifically distinct from those found any- 

 where else,* but they also belong largely to distinct genera. Of 

 the fourteen genera represented, four are peculiar to the islands. 

 The rarity of continental visitors to the Galapagos, as compared 

 with the Azores, is to be attributed to the circumstance that these 

 islands are situated in a zone characterised by an absence of storm 

 winds. In the island of Juan Fernandez, situated in latitude 34 

 S., and only four hundred miles from the Chilian coast, there are 

 but five species of land-birds, and of this number two are peculiar. 

 In the Keeling or Cocos Archipelago, situated in the Indian Ocean 

 at about the same distance from the Sumatran coast as are the 

 Galapagos from the coast of South America, there is not a single 

 species of true (indigenous) land-bird, although snipes and rails 

 of the common Malayan species are sufficiently abundant ; and the 

 same is true in the case of the island of St. Helena, situated eleven 

 hundred miles from the nearest point of the continent of Africa, t 

 Of the twenty species of Passeres, or perching-birds, inhabiting the 

 Sandwich Islands about the most strictly oceanic of any group of 

 oceanic islands so-called, being situated fully two thousand miles 

 from the nearest continental coast-line, and the same distance from 

 the nearest island groups (Marquesas and Aleutian), if we except the 

 small and almost tenantless shell and coral reefs all the forms are 

 peculiar ; and, furthermore, in all cases but one or two they belong 

 to genera which are likewise confined to the islands. And even of 

 the twenty-four or more species of aquatic and wading birds that 

 have been observed on or about the islands, five a coot (Fulica 

 alai), a moor-hen (Gallinula Sandvichensis), a rail (Pennula Millei), 

 and two ducks (Anas Wyvilliana and Bernicla Sandvichensis) are 

 peculiar. 23 All in all there are some fifty species of birds known 

 from the island group, of which about one-half are peculiar. 

 It is evident that migrants (true land-birds) from distantly re- 

 moved countries but rarely arrive here. In the case of the Ber- 



* The Dendroeca aureola, a species of wood-warbler closely allied to the 

 " golden" or summer warbler of the United States (D. sestiva), is only doubt- 

 fully separable from the D. petechia of the Island of Jamaica. 



t A small wading-hird of the genus vEgialitis (J2. Sanctse Helenas), allied 

 to a species of plover common in South Africa, is found in the island. 



