Extracts from the tentacles of Chironex fleckeri (Cnidaria) were resolved into two lethal fractions by chromatography on CM-Sephadex C-50. These were apparently identical to the two fractions previously resolved on Sephadex G-200. The hemolysin in the extracts was also examined by thin-layer chromatography on Sephadex G-200 and by various electrophoretic techniques. It was shown that the hemolysin associated markedly with the various support media, which made electrophoresis of little use. The tentacle extracts and a toxin obtained by a milking technique were compared by chromatography and shown to be very similar if not identical in their biological activities. Some data on the stability of the hemolysin was also obtained.