When variously coloured rabbits are set free in Europe, and are thus placed under their natural conditions, they generally revert to the aboriginal grey colour; this may be in part due to the tendency in all crossed animals, as lately observed, to revert to their primordial state. But this tendency does not always prevail; thus silver-grey rabbits are kept in warrens, and remain true though living almost in a state of nature; but a {112} warren must not be stocked with both silver-greys and common rabbits; otherwise "in a few years there will be none but common greys surviving."[266] When rabbits run wild in foreign countries, under different conditions of life, they by no means always revert to their aboriginal colour. In Jamaica the feral rabbits are described as "slate-coloured, deeply tinted with sprinklings of white on the neck, on the shoulders, and on the back; softening off to blue-white under the breast and belly."[267] But in this tropical island the conditions were not favourable to their increase, and they never spread widely; and, as I hear from Mr. R. Hill, owing to a great fire which occurred in the woods, they have now become extinct. Rabbits during many years have run wild in the Falkland Islands; they are abundant in certain parts, but do not spread extensively. Most of them are of the common grey colour; a few, as I am informed by Admiral Sulivan, are hare-coloured, and many are black, often with nearly symmetrical white marks on their faces. Hence, M. Lesson described the black variety as a distinct species, under the name of _Lepus magellanicus_, but this, as I have elsewhere shown, is an error.[268] Within recent times the sealers have stocked some of the small outlying islets in the Falkland group with rabbits; and on Pebble Islet, as I hear from Admiral Sulivan, a large proportion are hare-coloured, whereas on Rabbit Islet a large proportion are of a bluish colour which is not elsewhere seen. How the rabbits were coloured which were turned out on these islets is not known.