CONTENTS 



PART I. 



CHAPTER PAGE 



I. INTRODUCTORY. MENDEL'S DISCOVERY i 



Introductory Some pre-Mendelian Writings Mendel's Discovery 

 Dominant and Recessive Segregation. Allelomorphism Homo- 

 zygote and Heterozygote. Purity of Type. 



II. THE MATERIAL INVESTIGATED 18 



List of Structural Characters in Plants and Animals List of Types in 

 which the inheritance of Colour has been studied Preliminary 

 Deductions Dominance and heterozygous characters Mendel's 

 system distinguished from that of Galton. 



III. NUMERICAL CONSEQUENCES AND RECOMBINATIONS . . 57 



-Representations of the F 2 Generation and Novelties due to Re-combina- 

 tion of Factors Compound Characters Combs of Fowls Hetero- 

 stylism White Flowers from Red x Cream. 



IV. HEREDITY OF COLOUR 74 



Factors determining Colours : the Ratio 9:3- 4 The " Presence and 

 Absence " Hypothesis, Epistatic and Hypostatic Factors Colours 

 of Mice Pied Types A Dominant Piebald. 



V. HEREDITY OF COLOUR (continued) 88 



Albinos giving Coloured Offspring; Reversion on Crossing Various 

 Kinds of Whites Stocks Orchids Pigeons Fowls Primula. 



VI. HEREDITY OF COLOUR (continued) ... .107 



Eye-Colours. Variations in Colour of the Iris Deficiency of Eye- 

 Pigments in some Coloured Types. 



VII. HEREDITY OF COLOUR (continued) 115 



The Genetics of Yellow Pigments in certain Animals. Yellow Mice not 

 breeding true The Case of Basset Hounds and the " Law of An- 

 cestral Heredity." Relation of this Principle to Mendelian Rules. 



VIII. HEREDITY OF COLOUR (continued) i3 2 



Various Specific Phenomena in Colour-Inheritance. Relation of Colour 

 to Hoariness in Stocks. Miscellaneous Cases. Colour of a Special 

 Part controlling that of other Parts Summary and Discussion 

 Subtraction-Stages. 



