Contents 



importance of Mendelism has been exaggerated Dominance 

 sometimes imperfect Behaviour of the nucleus of the sexual cell 

 Chromosomes Experiments of Delage and Loeb Those of 

 Cue'not on mice and Castle on guinea pigs Suggested modifica- 

 tion of the generally-accepted Mendelian formulae Unit 

 characters Biological isomerism Biological molecules Inter- 

 pretation of the phenomena of variation and heredity on the 

 conception of biological molecules Correlation Summary of 

 the conception of biological molecules. 



CHAPTER VI 



THE COLOURATION OF ORGANISMS . . .170 



The theory of protective colouration has been carried to absurd 

 lengths It will not bear close scrutiny Cryptic colouring 

 Sematic colours Pseudo-sematic colours Batesian and 

 Mullerian mimicry Conditions necessary for mimicry 

 Examples Recognition markings The theory of obliterative 

 colouration Criticism of the theory Objections to the theory of 

 cryptic colouring Whiteness of the Arctic fauna is exaggerated 

 Illustrative tables Pelagic organisms Objectors to the Neo- 

 Darwinian theories of colouration are to be found among field 

 naturalists G. A. B. Dewar, Gadow, Robinson, F. C. Selous 

 quoted Colours of birds' eggs Warning colouration Objec- 

 tions to the theory Eisig's theory So-called intimidating 

 attitudes of animals Mimicry The case for the theory The 

 case against the theory " False mimicry " Theory of recogni- 

 tion colours The theory refuted Colours of flowers and fruits 

 Neo-Darwinian explanations Objections Kay Robinson's 

 theory Conclusion that Neo-Darwinian theories are untenable 

 Some suggestions regarding the colouration of animals 

 Through the diversity of colouring of organisms something like 

 order runs The connection between biological molecules and 

 colour Tylor on colour patterns in animals Bonhote's theory 

 of pcecilomeres Summary of conclusions arrived at. 



CHAPTER VII 



SEXUAL DIMORPHISM . . . . .297 



Meaning of the term Fatal to Wallaceism Sexual Selection The 

 law of battle Female preference Mutual Selection Finn's 

 experiments Objections to the theory of Sexual Selection 

 Wallace's explanation of sexual dimorphism stated and shown 

 to be unsatisfactory The explanation of Thomson and Geddes 

 shown to be inadequate Stolzmann's theory stated and criticised 



XV 



