Possible invertebrate intermediate hosts ofAnisakis simplex(Rudolphi, 1809, det. Krabbe, 1878),Thynnascaris adunca(Rudolphi, 1802), andPseudoterranova(=Phocanema) decipiens(Krabbe, 1878) were determined from examination of stomach contents of teleosts which are regularly infected by these parasites. The euphausiid,Nyctiphanes australis,and the galatheid crab,Munida gregaria,are possible sources ofA. simplexlarvae.M. gregariais a definite source ofT. aduncalarvae (and adults). Smaller zooplankton (e.g., copepods and decapod larvae) could also be sources ofT. aduncalarvae. No potential hosts ofP. decipienslarvae were apparent. Naturally occurring invertebrate hosts of anisakids were found in plankton samples.A. simplexlarvae were found inN. australis. T. aduncalarvae occurred in chaetognaths(Sagittaspp.), a medusa, and a decapod larva. These anisakid larvae are all morphologically similar to Stage III larvae from teleosts. Experimental infection ofN. australisandM. gregariawith Stage II larvae ofA. simplexandT. aduncawas unsuccessful. Infection rates, host specificity, and larval morphology are discussed.