VARIATION AND HEREDITY 133 



It is interesting now to inquire into the 

 occurrence of this remarkable mode of inherit- 

 ance, which is seen when the parent forms 

 have opposite or contrasted characters which 

 do not blend. The striking fact is the diver- 

 sity of the organisms in which it has been 

 demonstrated in the short period since 1900, 

 e.g. in mice, rats, rabbits, guinea-pigs, cattle, 

 poultry, canaries, snails, silk-moths; in beans, 

 maize, wheat, barley, stocks. Another strik- 

 ing fact is the great variety of characters 

 to which it applies, e.g. shades of colour, 

 peculiarities of fur and feathers, abnormal 

 features like extra toes, subtle qualities like 

 " broodiness " in hens, early ripening or 

 immunity to rust in wheat, and so on. 



Let us give a few examples, arranged in 

 parallel columns. 



ANIMALS 

 Dominant character. Recessive character. 



Hornlessness in cattle. Presence of horns. 



Normal short hair in Long " Angora " 



rabbits and guinea- hair. 



pigs. 



Short tail in Manx cat Normal length of 



(somewhat imper- tail. 



fectly). 



Normal movements in Waltzing in mice. 



mice. 



