Studies on the morphology and life-cycle ofDiplostomum (Diplostomum) gasterostei(Strigeida: Trematoda)

One of a large number ofLymnaea peregra(Mull.) from a pond near Glasgow was found to be infested withCercaria diplostomi gasterostei. C. d. gastrosteihas been found to penetrateGasterosteus aculeatusand develop into a diplostomulum in the retina of the eyes. Large numbers ofG. aculeatusfrom the pond have been found withDiplostomulum gasterosteioccurring in the retina. Infested heads of fish were fed to domestic ducklings and pigeons, and adult stages of a worm considered to be a new species and namedD. gasterosteiwere obtained. Morphological details of the cercaria, diplostomulum and the adult worm are described. The author wishes to thank Dr C. A. Hopkins for reading and criticising the manuscript, Dr D. A. Erasmus and Dr G. Rees for valuable suggestions. My thanks are due also to the technical staff of the Department who assisted me in the collection of snails and fishes, and to Mr Francis Deen who did the sectioning of the specimens. This work was in part supported by a grant from Shell Oil Company (London).