Abstract The fine structure of haemocytes in the freshwater mite Unionicola tetra/uTcatus is described and compared with other species of invertebrates. The present study reveals that the haemocytes consist mainly of two types; agranulocytes and granulocytes. The granulocytes is subdivided into 7-types (I-VD). The granulocytes are more abundant, larger in' size with smaller nuclei and larger amount of granulated cytoplasm. ... Read more