48 



PHYSICAL BASIS OF HEREDITY 



of each V-shaped chromosome pointed as the cell went 

 into the resting stage. It appears then that the chromo- 

 somes not only retain tlieir original orientation, but that 

 the ends of homologous chromosomes have already come 



a 



r:: 

















<^ti<i^ / t 



•v 



Fig. 20. — Synaptic stages and those immediately following in Batracoseps. (After Janssens.) 



together, or are coming together, as the following 

 stages show clearly. 



The union that begins at the ends (Fig. 20, e) grad- 

 ually extends along the length of the chromosomes, which 



