Literature Cited. 105 



centripetal effect on the nuclei. We also concluded that 

 karyogenetic characters were not as a rule recapitulatory, because 

 they imply a change in the nuclear unit which is transmitted by 

 mitosis to every cell, while organismal characters may become so 

 by adding on certain stages to the life-cycle of the organism. The 

 existence of these two types of characters accounts for many 

 anomalies in the biogenetic law. The existence of two such 

 classes of characters makes it possible to understand better many 

 features of organic structure and inheritance. 



But it is obvious that the relationship between these two 

 types of characters cannot be fully understood in all their aspects 

 at the present time, nor can a sharp line always be drawn between 

 karyogenetic, cytogenetic and orthogenetic characters in some 

 aspects they shade into each other. As a constructive attempt to 

 harmonize two bodies of evidence which are obviously in conflict 

 and have long been considered irreconcilable, we make no apology 

 for its tentative character and incompleteness. 



LITERATURE CITED. 



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Allen, Charles E., 1919. The basis of sex inheritance in Sphaerocarpos. 



Proc. Amer. Phil. Soc., 58 : 289-316, figs. 27. 

 Balfour, Bayley, 1917. Observations on Rhododendron seedlings. 



Trans, and Proc., Bot. Soc., Edin. 27: 221-227. 

 Bartlett, H. H., 1914a. An account of the cruciate flowered CEnotheras of 



the sub-genus Onagra. 



Amer. Journ. Bot. 1 : 226-243, figs. 2, pis. 19-21. 



,, ,, 1914b. Twelve elementary species of Onagra. 



Cybele Columbiana 1 : 37-56, pis. 5. 



,, 1915a. Mutation "en masse." 



Amer. Nat. 49 : 129-139, figs. 9. 



,, 1915c. The mutations of CEnothera stenomerts. 



Amer. Journ. Bot. 2 : 100-109, figs. 4. 

 ,, ,, 1915e. Systematic studies on CEnothera, 5. 



Rhodora 17: 41 44, pi. 3. 



Bateson, W., 1909. Mendel's principles of heredity. 



Cambridge University Press, pp. 396, figs. 37, pis. 6. 



,, 1913. Problems of Genetics. 



Oxford University Press, pp. 258, figs. 13, pis. 2. 

 1919. Dr. Kammerer's testimony to the inheritance of acquired 



characters. Nature 103 : 344-5. 



and E. R. Saunders, 1902. Experimental studies in the 



physiology of heredity. Reports of Evolution Com- 

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and Ida Sutton, 1919. Double flowers and sex linkage in 

 Begonia. Journ. Genetics, 8 : 199-207, pi. 8. 



