Morphological characterization and size of hemocytes in Anodonta cygnea.

The Anodont (Anodonta cygnea) constitutes one of the most important bivalves along of Anzali Lagoon. In last decade, Anodont have suffered a high degree of mortality. Description of the morphological characterization of hemocytes is a prerequisite to further exploring the causes of death in bivalves, therefore in this study; the circulating hemocytes of the A. cygnea in Anzali Lagoon were identified. At first, two types of hemocytes were recognized, granulocytes and agranulocytes, were identified based on the existence of cytoplasmic granules under light microscopy. The hemocytes were then stained and the granulocytes subclassified into eosinophilic and basophilic granulocytes and intermix. The eosinophilic granulocytes have distinct small and large granules. Agranulocytes could be subdivided into hyalinocytes and blast-like cells and another cell type, vesicular cells, was observed as unclassified cells. Results were compared with similar researches about other bivalves' observations.