IX] HEREDITY AND SEX 125 



to diiferent allelomorphic pairs in the sweet-pea and 

 other flowers, quite apart from sex. Sweet-pea 

 flowers are of two shapes, with 'erect' standards 

 or with 'hooded' standards. The erect character 

 is dominant to the hooded. Among the off^spring 

 of certain sweet-peas heterozygous for this pair 

 of characters and also for purple and red flowers, the 

 purple ofispring include both erect and hooded 

 standards, but the reds are nearly all erect. This 

 means that in the formation of the germ-cells the 

 purple factor and the erect factor go into diflferent 

 germ-cells, so that instead of four kinds of germ- 

 cells being produced in equal numbers, two are 

 produced in great excess, viz. purple-hooded and red- 

 erect. These meeting at random give purple-hooded, 

 purple-erect and red-erect, but hardly any red-hooded. 



It has recently been discovered by Bateson and 

 Punnett that the purple and erect factors go chiefly 

 into difierent germ-cells if introduced into the 

 heterozygote by diflerent parents, but are ' coupled ' 

 together and go into the same germ-cell if introduced 

 from the same parent. In the case of the Currant 

 Moth the G character is always introduced into the 

 female from the male and possibly for this reason is 

 never borne by female-bearing eggs. 



It has been seen that the case of the Currant 

 Moth and the similar cases in Fowls and Canaries lead 

 to the inevitable conclusion that in these animals 



