A good account, worth the attention of anyone who might think of naturalizing any foreign animal, reaches me from the Continent on the subject of a certain large rat that is troubling farmers and landowners in Czecho-Slovakia. Because of its depredations, as I reported the other day, the law prohibiting the use of traps has been modified. The rat is the Musk rat or Musquash. Some twenty years ago a Bohemian landowner of royal connexions released a few pairs on his estate near Prague, where they multiplied rapidly and whence they have now spread at least as far as Thuringia. In Saxony there are already official Government " Musk rat hunters," and large premiums are offered for the capture of the rats. There are stories of these big rodents attacking children ; and they are not necessarily untrue. One knows of parallel examples even in England in regard to both stoats and grey rats. However, the reason of their excom- munication is the damage they inflict on river and canal banks by their burrowing. They do in a big way what moles are doing in a smaller way to the banks in Eastern England.