Abstract
1. The hormone intermedin was injected into Xenopus larvae to induce pigment cell expansion. In the expanded condition melanophores were cut and macrophage ingestion of melanin granules and cell fragments was observed. 2. Macrophages retained parts of the ingested pigment cells for from one to five weeks. However, in no instance were these macrophages observed to synthesize melanin or to exhibit the physiological characteristics of melanophores as judged by their responsiveness to intermedin. 3. Preliminary observations on the influence of intermedin on nucleated and non-nucleated fragments of melanophores suggest that the cytoplasm of these pigment cells requires the presence of the nucleus in order to respond to the expanding stimulus of this hormone.