A New Gorgoderid Cercaria Parasitic in Lampsilis ventricosa Barnes

A new apharyngeate, styleted cercaria with a motile, filamentous tail has been found to develop in Lampsilis ventricosa Barnes in Lake Erie. It was determined that this trematode possessed characters common to the GORGODERINAE Looss, 1899, but belonged to a type not yet described for this subfamily. Bivalves were collected during 1951 and the spring of 1952 and examined for emerging cercariae which were studied alive, stained with neutral red and nile blue sulphate. Measurements were taken from specimens killed in warm A.F.A. fixative and cleared in glycerine. Sectioned material was stained with Heidenhain's iron haematoxylin, Mallory's triple, thionin blue and toluidine blue. This study was financed by the Ohio Division of Wildlife. The author is indebted to Dr. G. R. La Rue for many valuable suggestions and to Dr. E. W. Price for checking the availability of the specific name.