THE MYELOERYTHROID NATURE OF THE CHLORAGOGENOUS-LIKE TISSUES OF THE ANNELIDS

1. Chloragogenous, extravasal, intravasal and botryoidal tissues occur alternatively in various types of annelids. These tissues are sources of extracellular respiratory pigments. Considering their peritoneal origin, their structural and functional similarities we propose the term ''chloragogenous-like tissues'' for their common designation. 2. The synthesis of haem-compounds plays a significant role in the development of the structural and functional characteristics of the chloragogenous tissues. Haemoglobin is released into the blood plasma but the haem-enzymes catalase and peroxidase accumulate into the chloragocytes, moreover haem by products and damaged haem-compounds may be involved in the formation of chloragosomes. 3. Chloragocytes are in some way involved in the immune defence reactions. 4. We conclude that the chloragogenous-like cells are specific myelo-erythroid cells of the annelids.