ON THE TENDENCY OF SPECIES TO EOKM VARIETIES. 45 



On the Tendency of Species to form Varieties ; and on the Per- 

 petuation of Varieties and Species by Natural Means of 

 Selection. By Ciiaeles Dabwin, Esq., F.E.S., E.L.S., & 

 F.G-.S., and Alfred Wallace, Esq. Communicated by Sir 

 Charles Lyell, E.E.S., F.L.S., and J. D. Hooker, Esq., 

 M.D., V.P.E.S., E.L.S., &c. 



[Read July 1st, 1858,} 



London, June 30th, 1858. 

 My Dear Sir, — The accompanying papers, which we have the 

 honour of communicating to the Linnean Society, and which all 

 relate to the same subject, viz. the Laws which affect the Pro- 

 duction of Varieties, Eaces, and Species, contain the results of the 

 investigations of two indefatigable naturalists, Mr. Charles Darwin 

 and Mr. Alfred "Wallace. 



These gentlemen having, independently and unknown to one 

 another, conceived the same very ingenious theory to account for 

 the appearance and perpetuation of varieties and of specific forms 

 on our planet, may both fairly claim the merit of being original 

 thinkers in this important line of inquiry ; but neither of them 

 having published his views, though Mr. Darwin has for many 

 years past been repeatedly urged by us to do so, and both authors 

 having now unreservedly placed their papers in our hands, w^e 

 think it w^ould best promote the interests of science that a selec- 

 tion from them should be laid before the Linnean Society. 



Taken in the order of their dates, they consist of ; — 



1. Extracts from a MS. work on Species*, by Mr. Darwin, which 

 was sketched in 1839, and copied in 1844, when the copy w^as read 

 by Dr. Hooker, and its contents afterwards communicated to Sir 

 Charles Lyell. The first Part is devoted to " The Variation of 

 Organic Beings under Domestication and in their Natural State ;'* 

 and the second chapter of that Part, from which we propose to 

 read to the Society the extracts referred to, is headed, " On the 

 Variation of Organic Beings in a state of Nature ; on the Natural 

 Means of Selection ; on the Comparison of Domestic Eaces and 

 true Species." 



2. An abstract of a private letter addressed to Professor Asa 

 Gray, of Boston, U.S., in October 1857, by Mr. Darwin, in which 



* Tliis MS. work was never intended for publication, and therefore was not 

 written with care.— C. D. 1858. 



