234 Memorias de la Sociedad Poey. 



la Darwin-Wallace teoría de la selección natural, compartién- 

 dose entre ambos egregios naturalistas, entre el investigador 

 paciente del Archipiélago Galápagos y el no menos escrupulo- 

 so investigador del Archipiélago ludio, la gloria del famoso des- 

 cubrimiento. 



No es posible en una conferencia de esta índole dar cuenta 

 de los diversos e interesantísimos asuntos tratados en las obras 

 y publicaciones de Wallace, cuya relación expuse; por esto me 

 referiré únicamente a dos de sus libros: Contrihutions of the 

 Theory of Natural Selection (1871) y Man's Place in the Uni- 

 vers (1903). En el primero de ellos formula la ley que rige la 

 introducción de las nuevas especies y observa la tendencia de 

 las variedades a separarse indefinidamente del tipo primitivo, 

 la mímica y las otras semejanzas protectoras de los animales; 

 estudia el instinto comparativamente, exponiendo su teoría de 

 los nidos de las aves; y trata la selección natural en su aplica- 

 ción al hombre. Examinando los hechos de mimetismo, pene- 



and species, contain the results of the investigations of two indefatigable 

 naturalists, Mr. Charles Darwin and Mr. Alfred Wallace. 



' ' These gentlemen having, independcntly and uuknown to one another, 

 couceived the same very ingenious theory to aceount for the appearance 

 and perpetuation of varities and of specifie 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 niany years past been repeatedly iirged by us to do 

 so, and both authors having now unreservedly placed their papers in our 

 hands, we think it would best promote the interests of science that a 

 selection from them should be laid before the Linnaean Society. 



"Taken in the order of they dates, the consist of : 



"1. Extracts from a M. S. work on species, by Mr. Darwin, which 

 was sketched in 1839 and copied en 1844, when the copy Avas read by 

 Dr. Hooker, and its contents afterward communicated to Sir Charles Lyell. 

 The firts part is devoted to the variation of Organic Beings under Domes- 

 iication 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 Cariation of Organic Beings in a State of Nature; on 

 the Natural Means of Selections; on the Comparison of domestic Races 

 and True Species. 



"2. An abstract of a prívate letter adressed to Profesor Asa Gray, 

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

 his views and which shows that these remained unaltered from 1839 to 

 1857. 



"3. An essay by Mr, Wallace, entitled On the Tendency of Varieties 



