THEORY OF EVOLUTION 



131 













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Fig. 63. Conjugation of chromosomes (side to side union) in 

 the spermatogenesis of Batracoseps. (After Janssens.) 



some that meet in this way and always two of 

 the same kind. It has been observed that as 

 the members of a pair come together they oc- 

 casionally twist around each other (fig. 63, g, 

 1, and 64, and 6.5 ) . In consequence a part of one 



