The preservation of foxes for sporting purposes was evidently quite out of the range of thought at this not very distant epoch, and our author, in consequence, made a little mistake as to what men “ever” would do in the case of these noxious animals; but his general argument is sound, and it becomes much strengthened when we take into consideration the smaller vermin, such as stoats, weasels, moles, hedgehogs, fieldmice, vipers, toads, and newts, which would certainly not _all_ have been brought over by uncivilised man, even if any one of them might have been. But there is another reason why they were not so brought over. For on that supposition we should discover remains of fewer and fewer species as we go back into past times till at last when we reached the time of the first occupation of the country by man we should find none at all. But the actual facts are the very reverse of this. For the further we go back the more species of noxious and dangerous animals we discover, till in the time of the palæolithic (or oldest) prehistoric men, we find remains not only of almost every animal now living, but of many others still less likely to have been introduced by man’s agency. Such are the mammoths, rhinoceroses, lions, horses, bears, gluttons, and many others; and it is equally impossible that these could all have swum across an arm of the sea, which although only about twenty miles wide in its narrowest past, is yet so influenced by strong tides and currents that it becomes as effective a barrier as many straits of double the width. Owing, however, to the want of all definite ideas as to the mode by which the earth became stocked with animals and plants, the existence of identical species in countries separated by arms of the sea attracted very little attention till quite recent times. It is probable that Mr. Darwin was really the first person to see the full importance of the principle, for in his _Naturalist’s Voyage Round the World_, he remarks, that “the South American character of the West Indian mammals seems to indicate that this archipelago was formerly united to the southern continent.” Some years later, in 1845, Mr. George Windsor Earl called special attention to the subject by pointing out that the great Malay Archipelago may be divided in two portions, all the islands in the western half being united to each other and to the continent of Asia by a very shallow sea, and all having very similar productions, while many large animals, such as the elephant, rhinoceros, wild cattle, and tigers, range over most of them. We then come to a profoundly deep sea, and the islands of the eastern half of the archipelago are either surrounded by a deep sea or are connected by a shallow sea to Australia; and in this half the productions resemble those of Australia, marsupials being found in all the islands while the large quadrupeds of Asia are almost wholly unknown.