To mention an example, Colonel Feilden informs us (_Zoologist_, 1888) that, when living on the island of Barbadoes, an alligator arrived one day on the shore, and at the same time a tree measuring 40 feet in length, which was recognised as a Demerara species, was likewise stranded. He thinks that there can be no doubt that the alligator, which was alive when it reached Barbadoes, was transported by the tree, thus covering a distance of 250 miles from the nearest land. Numerous observations on the accidental transportal of seeds and tree-trunks from one island to another, and from a continent to an island, have been recorded, and even on our own shores we may witness the occasional arrival of such vegetable products from a far distant land. On the west coast of Ireland it not unfrequently happens that large West Indian beans are stranded, and in this as well as in many other similar cases the seeds have often proved none the worse for their prolonged immersion in sea-water. That locusts are sometimes blown to great distances from the land is not so surprising, since their power of steering through the air is very limited. Darwin mentions (p. 327) having caught one 370 miles from the coast of Africa, and that swarms of them sometimes visited Madeira. Sir Charles Lyell relates that green rafts composed of canes and brush-wood are occasionally carried down the Parana River in South America by inundations, bearing on them the tiger, cayman, squirrels, and other quadrupeds. But though actual observations of such abnormal instances of the dispersal of animals are few, many experiments have been made to demonstrate the possibility of a passive transportal of species over wide distances. It was especially Darwin who gave a great stimulus by setting the example to those interested in natural history in the conduct of such researches. He was struck by the fact that, though land-shells and their eggs are easily killed by sea-water, almost all oceanic islands, even the smallest and most isolated, are inhabited by them, and felt that there must be some unknown but occasionally efficient means for their transportal (p. 353). To quote his words: "It occurred to me that land-shells, when hibernating and having a membranous diaphragm over the mouth of the shell, might be floated in chinks of drifted timber across moderately wide arms of the sea. And I find that several species in this state withstand uninjured an immersion in sea-water during seven days: one shell, the _Helix pomatia_, after having been thus treated and again hibernating, was put into sea-water for twenty days, and perfectly recovered. During this length of time the shell might have been carried by a marine current of average swiftness to a distance of 660 geographical miles. As this _Helix_ has a thick calcareous operculum, I removed it, and when it had formed a new membranous one, I again immersed it for fourteen days in sea-water, and again it recovered and crawled away.