The chromatin network was revealed in DNA stained cell imprints of developing chick embryo chrondrocytes using the recently developed method of TV image processing. The network consists of two classes of alveoles. The large alveoles, which accompany large chromocentres, are concentrated at the centromeric nuclear pole representing the most stable part of the network. The small alveoles, connected with the small chromocentres and located around the chromosome arms and telomeric ends, are dynamic. These smaller alveoles appear in differentiating chondroblasts and disappear in ageing chondrocytes. Ectopic conjunctions involving constitutive and intercalary heterochromatin are responsible for the network formation.