ISSN 0022-1112. Crease across lower corner of rear cover. Contents are: Fish haematology - A bibliography, by R I Hawkins & L E Mawdesley-Thomas; The existence of natural hybrids between the European trout and the Atlantic salmon, by R H Payne, A R Child & A Forrest; Compensatory swimming in the kokanee and sockeye salmon Oncorhynchus nerka (Walbaum), by H H Harvey & C R Bothern; Neogobius fluviatilis in Lake Balaton - a Ponto-Caspian goby new to the fauna of central Europe, by P Biro; A simple electronic smolt counter, by D M Weiss; Some aspects of pathogenesis of infectious hematopoietic necrosis (IHN), by W T Yasutake & D F Amend; Immune relations between mother and foetus in the viviparous poeciliid fish Xiphophorus hellerii Haeckel - I - Antigenicity of the foetus, by P J Hogarth; Immune relations between mother and foetus in the viviparous poeciliid fish Xiphophorus hellerii Haeckel - II - Lack of status of the ovary as a favourable site for allograft survival, by P J Hogarth; On