REPTILIAN SPERMATOGENESIS 317 



teen macro-chromosomes would have become females, without 

 doubt. 



13. There is a remarkable constancy in the number and size 

 of the macro-chromosomes of all the species of the family Iguani- 

 dae studied. All six species reported on show twelve macro- 

 chromosomes in dividing spermatogonia, and in every case at 

 least three pairs of the chromosomes are strikingly alike in size 

 and shape. 



14. Syncytial masses and giant spermatozoa are commonly 

 found in the testes of all the lizards studied. 



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