The neurotoxic effects on shore crabs displayed a range of effective paralytic doses with a 15- fold difference between the most potent and least potent anemones. Similarly, the dose range for Artemia toxicity was 100- fold and for haemolysis was 1000-fold which is consistent with the range of toxicities Tipiracil hydrochloride reported by Senc��ic�� and Mac��ek for a group of non-host anemone species. Our findings also compare well with a study by Mebs on purified cytolytic toxins, 6-Thio-2-Deoxyguanosine showing that H. magnifica had a significantly greater haemolytic effect than E. quadricolor with a similar magnitude of difference between the EC50 concentrations. Our study differed from Mebs who did not identify haemolytic activity for H. crispa venom. This difference may be due to a loss or reduction in toxin concentration during the purification process used by Mebs. Although some dose response curves were classically sigmoidal, allowing a clearly defined 50% effective concentration to be determined, in other cases a non-sigmoidal character was observed. This may be a result of the crude venom containing a variety of active compounds of differing potency and/or mechanism of action which has been shown for many anemone species elsewhere. This may cause some deviations between true potency and the potency we have measured. However, the scale of these deviations appears to be small relative to the much larger variations between the venoms from different anemone species. Another factor that may have resulted in the underestimation of actual toxicity is the use of total protein of the crude venom as a relative measure of toxins. The crude venom would have contained non-venom proteins and thus the LD50 and EC50 venom concentrations reported may be higher than would result if the assays were conducted with the purified venoms. However, we believe the comparative potencies using crude venoms reported in this study are indicative of the toxicity of venoms delivered in nature. Generally there was strong concordance between the rank toxicity of venoms in the three test approaches, suggesting that those with the highest haemolytic potential were also those that were more toxic to Artemia.