☞ Of morphons there are six orders or categories: 1. Plastids or elementary organisms. 2. Organs, homoplastic or heteroplastic. 3. Antimeres (opposite or symmetrical or homotypic parts). 4. Metameres (successive or homodynamous parts). 5. Personæ (shoots or buds of plants, individuals in the narrowest sense among the higher animals). 6. Corms (stocks or colonies). For orders 2, 3, and 4 the term idorgan has been recently substituted. See Idorgan.