138 THE THEORY OF THE GENE 



The embryonic development of triploid individuals is 

 expected to be normal because of the balanced condition 

 of the genes. The only inharmonious factor that may 

 enter into the situation is the relation between three sets 

 of chromosomes and the inherited quantity of cytoplasm. 

 How far auto-regulation takes place is not definitely 

 known, but it may be surmised that in plants at least the 

 cells of the triploid are larger than those of the normal 

 type. 



Other triploid types that have arisen or have been pro- 

 duced by crossing wild species, one of which has twice as 

 manv chromosomes as the other, will be described in a 

 later chapter. 



the Fj hybrid one or more of the chromosomes appear to conjugate at 

 times. Probably reduction follows for this pair, which would change by one 

 or more the actual number of chromosomes in the germ-cells of the r2 

 individuals. 



