INTRODUCTION Difficulties with the identification of some West-Indian Belonidae and an investigation into the merits of the generic name Strongylura as against Tylosurus led to a revision of the Belonidae, the result of which is published here. As will be seen on the following pages, this revision is by no means final; many problems remain to be solved, much synonymy given here is doubtful, lack of material prevented me from investigating the possible presence of slight geographic variation in the widely distributed species; some apparently valid species are left out altogether (I listed their names on p. 5) because no material has been available, and other names remain doubtful as it has not been possible to examine the type specimens. There is also the possibility that in a few instances I have too recklessly united species — or at least geographically representative forms — which in future may be found to be valid subspecies. Nobody can be more aware of all these shortcomings than I am, but I had to consider the fact that I was leaving Leiden, and rather than run the risk that the notes hitherto assembled would never be published, I chose to present them even in an incomplete form. Considering the great confusion the nomenclature and systematics of the Belonidae are in at the moment, I believe that these notes, however preliminary they may be, will be useful to students of the group. The Belonidae form a well-defined natural group consisting (as my investigations show) of not over about 30 species. Because of its smallness one is inclined to wonder if this group really deserves family status. Though for the moment I follow an authority as Berg (1940, 1955) in considering