532 PRIMARY FACTORS OF ORGANIC EVOLUTION. 



1894. Ryder, J. A. American Naturalist, p. 154. Orr's Theory 



of Development and Heredity. 

 1894. Cope, E. D. American Naturalist, p. 205. The Energy of 



Evolution. 

 1894. Cope, E. D. New Occasions, No. 6 (May), Chicago. The 



Origin of Structural Variations. 

 1894. Scott, W. B. American Journal Science and Arts, XLVIII. 



p. 355. Mutation and Variation. 



