1. The anaphase chromosome is composed of two intertwined chromonemata (chromatic threads) lying in a less chromatic matrix. 2. The duality of the chromosome is temporarily obscured during the “tassement polaire” or polar clumping stage. 3. At telophase, the less chromatic matrix of the chromosome gradually disappears and the chromonemata maintain the genetic continuity of the chromosome. 4. Individuality of the chromosomes and of the chromonemata are not recognisable in the Tate telophase and the resting stage of the nucleus. 5. Individuality of the chromosomes and of the chromonemata become again visible in the comparatively advanced prophase stage. 6. The less chromatic matrix reappears in the early prophase. 7. At the equatorial plate stage, each of the two chromonemata of a chromosome gives rise to two daughter chromonemata thus giving rise to a quadruple structure of the mother chromosome. In conclusion I wish to express my gratitude to Prof. S. P. Agharkar for facilities offered during the progress of this investigation. © 1936, Japan Mendel Society, International Society of Cytology. All rights reserved.