4IO Lamarck:, his life and work 



Karl Jordan* proposes the term " mechanical selec- 

 tion" to account for them, but he points out that 

 this factor can only work on variations produced by 

 other factors. Certain cases, as the similar variation 

 in the same locality of two species of different fam- 

 ilies, but with the same wing pattern, tell in favor 

 of the direct action of the local surroundings on the 

 markings of the wings. 



In the same direction are the essays of Schroederf 

 on the markings of caterpillars, which he ascribes to 

 the colors of the surroundings; of Fischer ;}: on the 

 transmutations of butterflies as the result of changes 

 of temperature, and also Dormeister's § earlier paper. 

 Steinach || attributes the color of the lower verte- 

 brates to the direct influence of the light on the pig- 

 ment cells, as does Biedermann.^ 



In his address on evolution and the factors of 

 evolution. Professor A. Giard ** has given due credit 

 to Lamarck as " the creator of transformism," and 

 to the position to be assigned to natural selection as 

 a secondary factor. He quotes at length Lamarck's 



* " On Mechanical Selection and Other Problems." Novitates 

 Zoologiccs, iii. Tring, 1896. 



\ Sntwicklung der Raupcnzeichnung und Abhdngigkeit der letzeren 

 von der Farbe der Umgebung, 1894. 



\ Transmutation der Schmetterlinge infolge Temperatur-verdnder- 

 ungen, 1895. 



§ Ueber den Einfluss der Temperatur hei der Erzeugung der 

 Schmetterli7Zgs-varietaten, 1 880. 



II Ueber Farbenwechsel bei niederen Wirbelthieren, bedingt durck 

 directe Wirkung des Lichts auf die Pigmentzellen. Centralhlatt fur 

 Physiologie, 1891, v., p. 326. 



T[ Ueber den Farbenwechsel der Frosche. Pfluger's Archiv fiir 

 Physiologic, i8g2, li., p. 455. 



** Lefon d' Ouverture du Qours de V Evolution des £tres organises, 

 Paris, 1888, and " Les Facteurs de VEvoXution.," Revue Scientifique, 

 November 23, 1889. 



