TETRAPLOIDS 123 



germ-cells with 24 chromosomes are those most likely to 

 survive and function. Some of these plants with more 

 than 48 chromosomes might give new types with still 

 greater irregularities of distribution of the chromosomes, 

 owing to the additional extra chromosomes. 



i^ </- 



^\%i^i^^ 





« 



ab 



Fig. 77. 



a, Euchlaena perennis, first maturation division, prophase; with 

 19 bivalents and two single chromosomes, ai, Metaphase of last. 

 a2. Anaphase of same, b, Zea mays, first maturation prophase with 

 ten bivalents. c, Euchlaena mexicana, first maturation division, 

 prophase, with ten chromosomes, ab. Hybrid (F^) between E. 

 perennis and Zea mays, prophase of first maturation division with 

 3 trivalent, 8 bivalent, and 5 single chromosomes, abi Same as 

 last, late anaphase of first maturation division. (After Longley.) 



