Redescription of the life cycle of Haemogregarina simondi (Laveran and Mesnil, 1901) in its vertebrate host the marine fish Solea solea (Linnaeus).

The life cycle of Haemogregarina simondi is described in its vertebrate host the marine flatfish Solea solea. An intraleucocytic schizogony is followed by an intraerythrocytic schizogony giving rise to eight gametocytes. A differentiation into micro- and macro-gametocytes was also observed and thus confirms the results of other authors for H. aeglefini, H. bigemina, and H. sachai. It is postulated that most if not all of the haemogregarines of marine fish undergo similar life cycles as the one described here.