MIGRATION 



of sheep and other food, together with a suitable climate, 

 would assist in their rapid increase, and once established, 

 the mischief would be beyond the power of the inhabitants 

 to stop or control. 



Great opportunities are afforded to migratory birds to 

 cross the sea. They are enabled to rest on at times large 

 floating masses, such as that commonly known as the 

 Gulf weed, which, according to some authors, is equal in 

 size to the area of Great Britain, and which not only 

 affords them a resting-place, but in many instances sup- 

 plies them with food, for these masses swarm with living 

 animals of endless kinds, insects, crustaceans, mollusca, 

 etc. 



Many years since a dead whale floated on the coast of 

 Devonshire ; it was almost white, being thickly covered 

 with the grey phalaropes ; many hundreds of these beauti- 

 ful and rare British birds congregated upon the floating 

 carcass, and no doubt fed upon parasites and other 

 creatures that infested it, and on portions of fat. These 

 birds were quite tame, and the boys about Devonport and 

 Plymouth killed great numbers of them with sticks ; had 

 these birds not met with such wanton destroyers they 

 might, in all probability, have established themselves on 

 our shores, as one or two instances are recorded of their 

 being found in this country in the breeding season, 

 although their great breeding-ground is, according to Mr. 

 Yarrell, in the Arctic regions. Porpoises of various species, 

 sea-gulls and other fish-eating birds, and fish-devouring 

 fishes, follow to our shores the shoals of smaller fry upon 

 which they feed, just as the lions and other carnivora 

 follow, across the land, the herds of antelopes, and thus 

 distribute and spread their kind. 



In the second volume of Sir Charles Lyell's Principles 

 of Geology is a chapter upon migration of plants and 



233 



