188 PRINCIPLES OF ANIMAL BIOLOGY 



Thus it may be assumed that the sperm in ordinary fertilization plays 

 a dual role. It brings in a substance or substances which initiate 

 development and in its nucleus it brings chromosomes which partici- 

 pate in the control of heredity. 



References 



Hegner, R. W. The Germ Cell Cycle in Animals. (Especially Chapters I and II.) 

 Lankester, Ray. Diversions of a Naturalist. (Chapter XXV, History of the 



Barnacle and the Goose.) 

 LocY, W. A. Biology and Its Makers. 



LoEB, J. The Organism as a Whole. (Chapters III and V.) 

 LoEB, J. Artificial Parthenogenesis and Fertilization. 

 MiALL, L. C. The Early Naturalists and Their Lives. (Especially pp. 225-228, 



concerning Redi.) 

 MiNCHiN, E. A. Introduction to the Studj' of the Protozoa. 

 OsBORN, H. F. From the Greeks to Darwin. (For references on abiogenesis, see 



index.) 

 Thomson, J. Arthur. The Study of Animal Life. (Chapter XIV.) 

 Wilson, E. B. The Cell in Development and Inheritance. (Chapters III and IV.) 



