Chapter VI: 170

The Colouration of Organisms

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 Müllerian
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—Objections 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
recognition 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 pœcilomeres—Summary of
conclusions arrived at.

CHAPTER VII 297

Sexual Dimorphism

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—Neo-Lamarckian
explanation of sexual dimorphism stated and criticised—Some
features of sexual dimorphism—Dissimilarity of the sexes probably
arises as a sudden mutation—The four kinds of mutations—Sexual
dimorphism having shown itself, Natural Selection determines
whether or not the organisms which display it shall survive.