| Abstract: | Glia cells were examined in the brains of a mature platypus and an immature echidna. In the echidna a few dark, organelle-rich glia cells were encountered. The lighter glia cells had resemblances with the single type of glia cell encountered in the brain of the platypus. These cells were characterised by highly homogeneous areas of nuclear chromatin and light cytoplasm containing dark, finely granular condensations which frequently surrounded Golgi membranes. Microtubules were present within the cytoplasm but neither filaments nor glycogen-like particles were encountered. It was concluded that the cells described conformed to the types of neither astrocytes nor oligodendrocytes as encountered in metatherian and eutherian mammals. Among their functional capacities such cells presumably include, either in the immature or mature forms, the roles of both astrocytes and oligodendrocytes. |
