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Y. TANAKA. 
repulsion are not fundamentally different phenomena, but they are dependent 
on the manner in which the ‘presence’ characters, A and B for instance, are 
brought into the cross. A coupling occurs when A and B are brought in 
by the same parent, but a repulsion takes place when they come from 
different parents. 
As to the process which gives rise to the assumed partial gametic series, 
Bateson and Punnett put forth a suggestion (1911, b) that the case may be 
easily understood if we suppose as multiple reduplication of certain gametic 
forms (AB and ab in coupling, Ab and aB in repulsion) effected in the 
gametogenesis. 
Collins maintains the possibility of the occurrence of intermediate gametic 
series such as 2:1, 4:1, 5:1, 6:1, etc., besides those assumed by 
Bateson and others, i. e., 3 : 1, 7 : 1, 15 : 1, 63 : 1, and so forth. 
Baur suggests not only the occurrence of some intermediate systems, but 
also possible existence of n : 1 : 1 : x series, in which x is greater than n. 
VIII. General Discussion and Conclusion. 
In the foregoing pages, I have described six cases of repulsion and 
coupling observed in the Silkworm. All of them occurred between the 
yellow colour of the cocoon and the marking characters of the larva, except 
a single case of repulsion which took place between two marking factors. 
These cases may be summarized as follows : 
1) Complete repulsion between Normal marking and Yellow colour. 
2) Complete repulsion between Striped marking and Yellow colour. 
3) Complete repulsion between Striped marking and Normal marking. 
4) Partial coupling between Moncaud marking and Yellow colour. 
5) Partial coupling between Striped marking and Yellow colour. 
6) Complete coupling between Striped marking and Yellow colour. 
The evidence for the occurrence of these reduplicated systems rests, in 
some of these cases, upon the result of a single mating, but in others it rests 
