X 
PREFACE. 
thence.* t There are, however, instances of islands situated suffi- 
ciently near large continents to admit of the flight of birds from the 
latter, and yet deriving comparatively few, or none of their species 
from them. The most remarkable example is presented by the 
Galapagos archipelago, situated under the equatorial line, and 
which, though only 500 to 600 miles westward of the coast of 
South America, does not contain a land bird from the continent. 
Even some of the islands of the group have their peculiar 
species. J Eull information on this most interesting subject will be 
found in Mr. Darwin's excellent journal, kept during the Survey- 
ing Voyages of H.M.S. Adventure and Beagle, vol. iii. p. 461 
and 473-478. Madagascar, the nearest part of which is only 
about 250 miles distant from the coast of Africa and extending 
about 1,000 miles in a parallel direction, offers another striking 
instance of an island not deriving its fauna from the neigh- 
bouring continent. Of 113 known species of birds of Mada- 
gascar, 68 are peculiar to it. The fullest information on the sub- 
ject of the ornithology of that island will be found in a compre- 
hensive essay by Dr. G. Hartlaub of Bremen, published in the 
Annals of Natural History for Dec., 1848, p. 383-396. Eor a 
knowledge of it, and its translation from a German journal, the 
English reader is indebted to Mr. H. E. Strickland. 
It is interesting to observe how birds are affected by the opera- 
* One species only, the red grouse, is peculiar to the British Islands. 
f These views were announced with great brevity in my Report on the Verte- 
brate Fauna of Ireland drawn up for the British Association for the Advancement of 
Science, and published in the volume for 1840. At the meeting of that Association 
held at Cambridge in 1845, Professor Edw. Forbes brought forward a very elabo- 
rate communication, accounting for the distribution of the species contained in the 
existing fauna and flora of the British Islands, on geological data. This highly 
interesting and remarkable essay (pp. 98) was subsequently published in the 1st 
volume of Memoirs of the Geological Survey of Great Britain. 
£ The flora of these islands is equally peculiar. See an admirable paper on this 
subject by Dr. Joseph D. Hooker in the Linnaean Transactions, vol. xx. part 2 (1847). 
