In the cytoplasm of primordial germ cells (PGCs) of Tetrodontophora bielanensis accumulations of nuage occurred. Before colonization of the gonads it had a fuzzy appearance (fibrous nuage), while after the PGCs had entered the gonads, the nucleolus-like bodies (granular nuage) were extruded from the cell nucleus, joined the fibrous nuage and formed the 'complex nuage'. After the application of the preferential RNA staining in the PGCs of T. bielanensis the fibrous nuage became completely bleached while the granular part remained unchanged. The fibrous nuage behaved exactly like DNA in the nucleus. To test for the presence of DNA in the nuage the DNAze and for the presence of RNA the RNAze digestions were applied. DNA was not found in the fibrous nuage nor in the complex nuage. However, the granular part of the complex nuage appeared to contain RNA. RNA.