IOO 



CHARLES V. MORRILL. 



in all its cleavage and blastoderm nuclei and the other 16. 

 These chromosome numbers are the same as those found in the 

 spermatogonia and oogonia respectively. The size-relations al>o 



e 



FIG. 6. Archimerus alternatus. Chromosome-groups of embryonic cells, 15- 

 chromosome type, a-e, from the same embryo; /-/, from other embryos. 



are in general the same as in the gonads. It seems fair then to 

 conclude that the is-chromosonu- embryos are males, the 16- 

 chromosome, females. In Fig. 6 are shown twelve 15-chromo- 



