OTHER THEORIES OF SPECIES-FORMING. 373 



discusses keenly the mutations of de Vries and finds in them noth- 

 ing radically different either in character or behaviour from the 

 Darwinian fluctuating variations. 



27 Conklin, E. C, Science, N. S., Vol. XXI, p. 525, 1905. 



28 Morgan, "Evolution and Adaptation," p. 292, 1903. 



29 Morgan, "Evolution and Adaptation," pp. 298-299, 1903. 

 References to 30 Emery, C, "Gedanken zur Descendenz- und 



theories explain- Vererbungstheorie," Biolog. Centralblatt, Vol. XIV, 



ing secondary pp. 397-420, 1893. 



sexual characters, si Cunningham, J. T., "The Species, the Sex, and 



the Individual/ Natural Science, Vol. XIII, pp. 184-192, 233-239, 



1898. 



32 Wallace, A. R., "Tropical Nature," 1878. 



33 Barrett-Hamilton, G. E. H., "Note on a Possible Mode of Origin 

 of some Nuptial and Sexual Characters in Vertebrates," Anatom. 

 Anzeig., Vol. XVIII, pp. 47-48, 1900. 



