Mr. Murray's views, though they relate only to oceanic islands, are likewise applicable to continental islands such as our own. I think we might take the admixture in the British fauna due to occasional, including human introduction, as amounting to five per cent. It is better to take a high estimate, so as to include all the species about whose native land there might be some reasonable doubt. Now of what importance, after all, is this five per cent.? The remaining ninety-five per cent. of the species of animals belonging to the British fauna undoubtedly migrated to these islands in the normal way by land. It is of great importance, in dealing with the question of the origin of the British fauna, to thoroughly grasp this conclusion--_that ninety-five per cent. of the animals have reached us by land_. We can afford in fact to ignore the five per cent. altogether. It is an insignificant factor. As regards the botanical aspect of the question, botanists are quite in accord with the zoologists, and entirely share their views in the belief of a former land-continuity between the British Islands and the Continent. "It cannot be denied," says Professor Blytt (p. 32), "that a plant of one or another species may, in an exceptional case, migrate, without human assistance, all at once, across large tracts of land and sea, and that such migration, if operating during geological periods, might introduce a number of species even into distant oceanic islands; but when the question is of whole communities of plants, such as the above enumerated elements in our flora, then such an accidental and sudden transport across large tracts can only be conceived to be at all probable in the case of Arctic plants carried by drifting ice to a bare country without native flora; as to the other species, we must imagine that the _migration during the gradual change of climate has proceeded slowly and step by step across connected tracts of country_. In that manner we may assume that our country has in the course of time obtained its present covering of plants. Each of the above-named elements in our flora has doubtless its corresponding element in our fauna. The fauna and flora of a region stand in relation of complicated dependence to each other. The animals live on the plants. The fecundation of the plants takes place in a great degree by means of insects; their seeds are often scattered by resident birds and quadrupeds. Everything indicates that _conveyance to small distances is the rule_, and that sudden and long migration is the exception."