APOMICTIC POLYPLOIDS 



469 



The chromosome numbers show that polyploidy and particularly 

 odd numbered polyploidy favours apomixis. Two reasons suggest 



Table 70 



Cases of Polyploidy within the Species Associated with the Occurrence 



of Apomixis 



Note.— No other animal polyploids are known except in the hermaphrodite 

 Helix pomatia (« = 12 and 24, cf. Wilson, 1928), and in experimental material 

 of Drosophila and Habrobracon. Polyploidy may be inferred very generally 

 in the Annelida and Mollusca from a comparison of chromosome numbers in 

 different species. 



themselves for this : (i) Meiosis is less regular in polyploids than in 

 diploids, for the reason that a too great likeness of the chromosomes 

 is here as serious a cause of irregularity as a too great dissimilarity 



