SUGGESTED READINGS 309 



ovulation of the egg in mammals. Deals also with the hormones involved in 

 ovulation and those active during pregnancy of higher mammals. 



Waterman, A. J., A Laboratory Manual of Comparative Vertebrate 

 Embryology, Henry Holt and Company, 1948. Very interesting tables of the 

 breeding habits of various vertebrates. 



Chapter 3 



Consult the books of Huxley and de Beer, Weiss, and Needham cited in 

 the readings for Chapter 1 . These books describe many more experiments on 

 the eggs of sea urchins, sea squirts, Amphioxus, worms, and various verte- 

 brates. Numerous operations on the egg and separation of the blastomeres 

 of dividing eggs are treated in detail. 



For gradients and the role of quantitative factors in the organization of 

 the egg, see Child, C. M., Problems and Patterns of Development. 



The morphology of various eggs and sperm is described in detail in 

 various textbooks — Shumway, Huettner, and McEwen, for example. 



The Chemistry of eggs and changes during development are to be found 

 in Needham's Chemical Embryology. 



For excellent photographs of various types of eggs see Waterman's A 

 Laboratory Manual of Comparative Vertebrate Embryology. 



Chapter 4 



The method of presentation of fertilization varies considerably in differ- 

 ent textbooks. For a comparative survey of fertilization in various species see 

 Chapter 3 of Shumway and Chapter 5 of Waterman. The latter has excellent 

 photographs of eggs in the ovary, eggs and sperm of various species, and 

 early cleavage in fish, sea urchin, frog, chick and mammal. There is also a 

 fine section on artificial insemination in farm animals and on sperm activity. 



Allen, Danforth, and Doisey's Sex and Internal Secretions is useful on 

 physiology of sperm, artificial insemination, and length of life of eggs. 



For a theory of fertilization as related to the general problem of stimula- 

 tion of cells by external agents, see Heilbrunn, L. V., An Outline of General 

 Physiology (second edition, W. B. Saunders and Company, 1943). This 

 special theory involves a release of calcium as the common factor among all 

 the various stimulating agents. 



