212 DARWINISM TO-DAY. 



better and larger capacity to adapt themselves during their 

 ontogeny to their needs win in the struggle for existence 

 rather than those born with predetermined slightly larger 

 leg, slightly stronger muscle, etc.? What is needed is 

 capacity to develop by use and functional stimulus a much 

 stronger muscle, a much swifter flight than the average. 

 Those individuals that are capable of such considerable and 

 really worth while ontogenetic adaptation will win in the 

 struggle for existence ; and while they may not hand down 

 by inheritance their actually acquired characters, will they 

 not hand down their inherited congenital capacity for con- 

 siderable and effective ontogenetic adaptation ? 



APPENDIX. 



1 For a fairly complete bibliography, with abstracts, of all the 

 important discussions of species-forming theories published since 

 1895, see L'Annee Biologique (ed. Y. Delage). For bibliography 

 and abstracts, also see Zoologischcr Jahresbericht, issued annually 

 by the Naples Zoological Station. See also discussions and notes 

 in various biological journals, as Biologischcs Centralblatt, Natural 

 Science (now discontinued). Nature, Science, American Naturalist, 

 etc. 



2 For a careful account and discussion of Weismann's work and 

 theories as far as developed up to 1893, see Romanes, "An Exami- 



ListofWeis- nation of Weismannism," 1893. Weismann's pres- 

 mann's evolution ent-day position and his arguments for the selection 

 papers. theories are set out in his "Vortrage iiber die De- 



scendenztheorie," 2 vols., 1902. which we may look on as consti- 

 tuting a manual of neo-Darwinism, treating all the more familiar 

 bionomic phenomena and conditions as explained by selection. 

 The following is a chronological list of the more important of 

 Weismann's publications : 



! 'Uber die Berechtigung der Darwin'schen Theorie," 1868. 



"Uber den Einfluss der Isolirung auf die Artbildung," 1872. 



"Studien zur Descendenztheorie : I, Uber den Saison-Dimorphis- 

 mus der Schmetterlinge," 1875. 



"Uber die Dauer des Lebens," 1882. 



"Uber die Vererbung," 1883. 



