Blood cells of <i>Fundulus heteroclitus</i> (L.)

Abstract

Much of the parenchyma of the normal pronephros of the adult Fundulus heterodilus , a euryhaline teleost, is haematopoietic tissue which was examined in cytocentrifuge preparations and plastic embedded thick sections. As we have not characterized many of the blood cells functionally, the terminology used is based on their morphological resemblance to similarly named cells in higher vertebrates. Approximately 80% of the non‐erythroid elements observed in the pronephros are mature eosinophilic granulocytes (48%), immature eosinophilic granulocytes (25%), or cells likely to be their precursors [e.g. small blast cells (6%) and large blast cells (2%)]. Although there are macrophages in the pronephros that are capable of endocytotic activity, the mature and immature granulocytes are not. The granulocytes are non‐specific esterase positive, PAS positive, acid phosphatase negative, and are capable of being mobilized by a RES activating agent, Ecteinascidia turbinata .