DARWIN, CHARLES and ALFRED RUSSEL WALLACE. On the Tendency of Species to form Varieties, and on the Perpetuation of Varieties and Species by Natural Means of Selection. In: Journal of the Proceedings of the Linnean Society. Zoology. Vol. III, No. 9. London, 1859. 8vo, original pink wrappers, uncut and unopened; minor chipping to upper right corner of cover; cloth folding case. FIRST EDITION. PMM 344a; Grolier/Horblit 23a.