xii LIST OF TABLES 



Chapter VI 



Table 24A. Chromosome Association in Polyploids .... 185 



25. Fertility showing the Origin of Polyploids after Hybridisation 1 87 



26. The Origin of Allopolyploids from Hybrids . . .190 



27. Polyploid Hybrids with Abnormalities of Chromosome 

 Constitution ........ 193 



28. Autotetraploids with Reduced Fertility .... 194 

 28A. Chromosome Pairing in Polyhaploids .... 201 



29. Pairing of Chromosomes in Hybrids and Hybrid Derivatives 

 of Polyploid Species ...... 208-213 



30. Polyploid Species of an Intermediate Type . . .214 



31. Pairing in an Intermediate Octoploid Plant, Bromus erectus 

 var. eu-erectiis . . . . . . . .215 



32. Autopolyploid Species and Mutants . . . . .216 



33. Polyploid Species with Variable Numbers of Chromosomes. 220 



34. Observations of Cell Size in Haploids, Diploids and Poly- 

 ploids . . . . . . . . .221 



35. Measurements of Cells in Haploids, Diploids and Polyploids 223 



36. Linear Measurements of Cells in Polyploid Derivatives . 224 



37. Examples of Polyploidy within the Species . . . 227 



38. Chromosome Numbers in the Phanerogama . . . 229 



39. Allopolyploid Species whose Origin can be Determined . 234 



40. Observations of Secondary Pairing at Meiosis . . . 242 



Chapter VII 



Table 41. Interlocking of Chromosomes at Meiosis .... 258 



,, 4 1 A. Results of Dyscentric Crossing-over ..... 269 



,, 42. Dyscentric Structural Hybrids . . . . .273 



,, 43. Secondary Structural Changes due to Crossing-over after 



Primary Changes . . . . . . .280 



44. Comparative Scope and Validity of Experimental and Direct 



Methods of Studying Crossing-over . . . .298 



Chapter VIII 



Table 45. Observations of Nucleolar Behaviour .... 306 



,, 46. Comparison of Cycles of Differential Condensation in 



Different Organisms . . . . . . .310 



47. Distribution of Chromosomes at Meiosis . . . .318 



48 A. Trisomic Organisms showing Differential Action of Chromo- 

 somes . . . . . . . . .319 



48B. Unbalanced Clonal Forms . . . . . .319 



49. Transmission of Extra Chromosomes of Triploids to their 

 Progeny ......... 320 



50. Transmission of Extra Chromosomes of Trisomies to their 

 Progeny . . . . . . . . -321 



51. Pollen Abortion in Da/wya . . . . . .321 



52. Effects of Abnormal Chromosome Constitution on Viability 322 



53. Distribution of Extra Chromosomes of the Triploid Nicotiana 

 paniculata (w = 12) X N. rusHca {n = 24) in the Back- 

 crosses to its Parents . . . . . • .327 



