200 MENDELISM 



though complementary allelomorphic pairs, which at 

 some moment in the phylogeny of the varieties have 

 each lost their complement.'* 



We may now proceed to pass in rapid review a 

 selection of the more remarkable instances of Mendel ian 

 inheritance which have been so far demonstrated. 



The ease with which characteristics of colour can be 

 distinguished and denned has naturally led to a good 

 deal of attention being paid to the phenomena of their 

 inheritance. In this way many cases of simple domi- 

 nance have been discovered in plants and in animals, 

 as well as several examples of reversion in F 15 followed 

 in both cases by a Mendelian segregation of characters. 



Thus the colours of many flowers afford perfectly 

 simple phenomena, whilst other cases, like the sweet- 

 peas and the closely similar case of stocks studied by 

 Miss Saunders, have required long and arduous ex- 

 periment for their elucidation. No case of this kind 

 hitherto examined has been definitely proved to be 

 non-Mendelian. 



Colour characters which follow Mendel's law have 

 been observed in mice, rats, rabbits, guinea-pigs, 

 pigeons, fowls, cats, and so on. In butterflies and 

 other insects, and even in snails, similar phenomena 

 have been descried. The study of the larger domestic 

 animals awaits for the present the proper endowment 

 of these researches. When this takes place the 

 inheritance of far more important characters than 

 colour will be adequately studied to the great profit 

 of all who are concerned in the breeding industry. 



* Proceedings of the Royal Society, B. vol. 77, p. 238. 



