92 BREEDING 



in the mice represented on Plate II. runs on tlie 

 same lines as that of, for instance, tallness and dwarf- 

 ness in peas, and colour in the Andalusian fowls. 

 All these three instances agree in the production 

 of " dominants," " hybrids," and " recessives " in 

 the second hybrid generation in the proportion 

 1:2:1 in every four, and differ in the character of 

 the hybrid which, in the case of stature in the peas 

 was indistinguishable from one parent, in the case 

 of colour in the fowls was intermediate between that 

 of the two parents, and in that of colour in the mice, 

 constituted a reversion to the ancestral type of 

 coloration. The mice, further, afforded an instance 

 of a cross in which two pairs of independently inherited 

 characters were involved. A closer consideration of 

 such cases will form the subject of the next chapter, 

 and the line of argument to be followed now will 

 lead us back again to the phenomenon of reversion, 

 and show how, at any rate, some cases of it may be 

 explained in the light of Mendelian phenomena. 



