抄録
1. The gametic chromosome number 6 (in both male and female) and the somatic number 12 (in male) of Spinacia oleracea were counted in agreement with the previous observations.
2. Cytologically no unequal pair of the chromosomes were observed in both sides of the sexes.
3. An inference was made from the genetic results hitherto reported that the female is homozygous and the male heterozygous for the sex determining factor or factors, namely, the present case suggests the X-Y type of sex determination where X-and Y-chromosomes are morphologically indistinguishable from each other and behave as the autosomes.
