In America, the process of extermination marches with the settlement of the various states. W. J. J. Allen records the absolute disappearance of the walrus from the Gulf of St. Lawrence, and of the moose, the elk, and the Virginian deer, from many of the states in which they formerly abounded. This also is true, to some extent, of the bear, the beaver, the grey wolf, the panther, and the lynx. The buffalo (_Bos americanus_) is being destroyed at the rate of two hundred and fifty thousand annually, and it is estimated that the number slain by hunters for their hides during the last forty years amounts to four millions. It has disappeared in the eastern part of the continent from many extensive tracts which it formerly inhabited. Among the ocean whales, both the right and the sperm have only been preserved from extinction by the fortunate discovery of petroleum, which has reduced the value of their oil, and thus lessened considerably the number of vessels equipped for the whale fishery. In South Africa, elephants and all other large game are being steadily exterminated within the several colonies. In Australia, we find that the seals which thronged the islands of Bass's Straits in countless thousands, at the period when Bass made his explorations there, have utterly disappeared. The bulk of them were destroyed by seal-hunters from Sydney within a few years after his discovery. The lamentable records of the _Sydney Gazette_ of that period show this, for they detail the return to port, after a short cruise, of schooners laden with from twelve to sixteen thousand skins each. The result of this has been that for many years past the number of seals has been limited to a few individuals, to be found on one or two isolated rocks off Clarke's Island, and on Hogan's group. The great sea-elephant, which, in Peron's time, still migrated for breeding purposes from antarctic regions to the shores of King's Island, where it is described by him as lining the long sandy beaches by hundreds, has been almost unseen there since the date of his visit, and its memory is only preserved in the names of Sea-Elephant Bay, Elephant Rock, &c. which are still inscribed on our charts. The introduction of the Dingo, by the Australian blacks in their southward migration, is supposed to have caused the extinction of the Thylacinus (_T. cynocephalus_), or striped Australian wolf, on the main land of Australia, where it was once abundant; it is now only to be found in the remote portions of the island of Tasmania. This destruction of one species by another is paralleled in our own country by the approaching extinction of the indigenous and now very rare black rat, which has been almost entirely displaced by the fierce grey rat from Norway.