No. 585] MODIFICATION OF CHARACTERS. 



500 



accession of a " spotting factor" is a gratuitous assump- 

 tion. Spotting appears rather to be the manner of ex- 

 pression of the character when the amount of pigment is 

 small. It must be said, however, that in some families 

 having no greater quantity of pigmentation there is a 

 strong tendency for it to remain uniformly distributed, 

 so that the whole bud is very pale red. 



LITERATURE CITED 

 Castle, W. E., and Phillips, John C. 1914. Piebald Rats and Selection; an 



Experimental Test of the Effectiveness of Selection and the 



Theory of Gametic Purity in Mendelian Crosses. Carnegie 



Publ. 'No. 195, pp. 56, pis. 3. 

 Davenport, C. B. 1906. Inheritance in Poultry. Carnegie Publ. No. 52, pp. 



136, pis. 17. 



Gates, R. R. 1914. Breeding Experiment s which Show that Hybridization 

 and Mutation are Independent Phenomena. Zeitschr. f. Abst. 

 u. Vererb., 11 : 209-279, Figs. 25. 



1915a. The Mutation Factor in Evolution. Macmillans, London, pp. 353. 



1915&. On Successive Duplicate Mutations. Biol. Bull, 29: In press. 



1915c. Some (Enotheras from Cheshire and Lancashire. Annals Mo. 

 Bot. Gard., 1: 383-400. Pis. 20-22. 



