xii Contents 



CHAPTER PAGE 



IX. GAMETIC COUPLING AND SPURIOUS ALLELOMORPHISM . 148 



Pollen-Shape and Flower-Colour. Axil-Colour and Sterile Anthers 

 Hooded Standard and Flower-Colour in Sweet Peas. 



X. HEREDITY AND SEX 164 



Evidence from Breeding Experiments. Bryonia Sex-limited Heredity. 

 The Horns of Sheep Colour-Blindness Sex and Spurious Allelo- 

 morphism. The Currant Moth The Cinnamon Canary The Silky 

 Fowl Aglia tau Cytological Evidence Summary. 



XI. DOUBLE FLOWERS . . . . . . . .196 



Miscellaneous Cases. Recessive and Dominant Doubling " Hose-in- 

 Hose " Flowers The Special Case of Double Stocks. 



XII. EVIDENCE AS TO MENDELIAN INHERITANCE IN MAN . 205 



Normal Characters Diseases and Malformations. Dominants Sex- 

 limited Dominants Recessives Notes on collecting Evidence. 



XIII. INTERMEDIATES BETWEEN VARIETIES AND THE "PURE 



LINES" OF JOHANNSEN 235 



Intermediates as Heterozygous Forms Subtraction-Stages of Dominants 

 Interfering Factors Fluctuational Forms "Pure Lines." 



XIV. MISCELLANEOUS EXCEPTIONAL AND UNCONFORMABLE PHE- 



NOMENA 245 



Crosses breeding true without Segregation. Parthenogenetic or Apo- 

 gamic Forms. Hieracium Sexual Forms Numerical Aberrations 

 Irregularities of Dominance Alternation of Generations Mater- 

 nal Characters in certain Seeds. 



XV. BIOLOGICAL CONCEPTIONS IN THE LIGHT OF MENDELIAN 



DISCOVERIES 266 



Nature of Units Nature of Segregation Moment of Segregation 

 Differentiation of Parts compared with Segregation Reversion and 

 Variation. " Bush " and " Cupid " Sweet Peas Mendelian Segre- 

 gation and Species Discontinuity in Variation Mendelism and 

 Natural Selection. 



XVI. PRACTICAL APPLICATION OF MENDELIAN PRINCIPLES . 291 



Meaning of Pure-bred Rogueing Raising Novelties A Practical Ex- 

 ample Unfixable Types Technical Methods Sociological Appli- 

 cation. * 



APPENDIXES 307 



PART II. 



1. BIOGRAPHICAL NOTICE OF MENDEL 327 



2. TRANSLATION OF THE PAPER ON HYBRIDISATION . . . 335 



3. TRANSLATION OF THE PAPER ON Hieracium .... 380 



BIBLIOGRAPHY 387 



INDEX OF SUBJECTS ... 403 



INDEX OF AUTHORS ... 411 



