1. Using the Ohnuki's hypotonic solution for the demonstration of spiral structure in human somatic chromosomes, a coiling structure of frog somatic chromosomes was studied in bone marrow cells.
2. Special hypotonic pretreatment and the routine air-drying method facilitated the exaggeration of coiling chromonemata embedded in the chromosome entities.
3. Though inner structure of the chromosomes was only defined to the major coils, the gyres of coiled chromonemata were recognizable in metaphase cells.
4. At the secondary constriction the chromonemata appeared usually as uncoiling entity.
5. The centromere region in the chromosome appeared to be characterized by a quadruple chromomere structure which was formed fibrous connections present between four dense spots.