Darwin, Charles and Wallace, Alfred R. On the tendency of species to form varieties. [Contained in the Journal of the Proceedings of the Linnean Society, volume III, no.9, London, 1858]. Octavo, pp.62, [ii], 64, unopened in the original printed blue wrappers, felt-lined quarter morocco box. Very slight foxing, in excellent state. The famous joint paper establishing that life on earth evolved by means of natural selection. The Darwin-Wallace paper, comprising pages 45-62 of this issue of the Journal, is now most often seen on the market as an extract from the cumulated annual volume or contained within that volume: in its present form, as originally issued in the wrappered quarterly part, it is especially desirable. Freeman 346: he identifies two concurrent issues, one in blue wrappers for the Fellows of the Society who took both the zoological and botanical parts of the Journal, as here, and the other in pink for those who took only the zoological parts.