A revision is made of the species of Haemogregarina found up to now in Bufo marinus L. from the Neotropical Region. Parasites in toads from the north, center, south and east of Venezuela are studied and descriptions are made of the agamic cycle of Haemogregarina darlingi Leger 1918; the schizogonic cycle of Haemogregarina aquai Phisalix 1930, proposing reclassify it as Karyolysus aquai (Phisalix) since its agamic cycle is carried through in endothelial cells, and Haemogregarina legeri nov. sp. A Toxoplasma is studied in the blood and viscera of Bufo marinus L. describing the pathology of affected organs, proposing the name Toxoplasma serpai nov. sp. for it. The actual state of the systematics of Toxoplasma parasites in poikilotherm vertebrates is discussed.