234 -^- ^- Stevens 



spermatocytes and spermatids, though ii's and 13's are occasion- 

 ally found in each individual. 



2 An unequal pair of heterochromosomes is present in the first 

 spermatocytes. The components of the unequal pair separate 

 producing dimorphic second spermatocytes, spermatids and sper- 

 matozoa. 



3 "Das accessorische Chromosom" of Zweiger appears to me 

 to be a precocious division of the smaller heterochromosome, giv- 

 ing rise to irregular numbers of chromosomes in the second sper- 

 matocytes. 



Bryn Mawr College 

 January lo, 1910. 



