I. Cellular Biology.- The extracellular matrix (mesoglea) of hydrozoan jellyfish and its ability to support cell adhesion and spreading.- Effects of tumor promoters and diacylglycerol on the transdifferentiation of striated muscle cells of the medusa Podocoryne carnea to RF-amide positive nerve cells.- The physiology of feeding in the ctenophore Pleurobrachia pileus.- Behavioural and ultrastructural studies on the sedentary platyctenean ctenophore Vallicula multifor-mis.- Problems of being a cell in a soft body.- An ultrastructural study of the polyp and strobila of Atorella japonica (Cnidaria, Coronatae) with respect to muscles and nerves.- Rhopalium development in Aurelia aurita ephyrae.- II. Developmental Biology.- Bud formation in the scyphozoan Cassiopea andromeda: epithelial dynamics and fate map.- Basic morphogenetic processes in Hydrozoa and their evolutionary implications: an exercise in rational taxonomy.- Regression and replacement of hydranths in thecate hydroids, and the structure of hydrothecae.- Differentiation of the interstitial cell line in hydrozoan planulae. I. Repopulation of epithelial planulae.- A low-molecular weight factor from colonial hydroids affects body proportioning and cell differentiation.- Polyp regeneration from isolated tentacles of Aurelia scyphistomae: a role for gating mechanisms and cell division.- III. Reproduction.- Larval development and survivorship in the corals Favia favus and Platygyra lamellina.- Spawning of hermatypic corals in Bermuda: a pilot study.- Annual cycle of gametogenesis and spawning in a tropical zoanthid, Protopalythoa sp..- Reproduction and developmental pathways of Red Sea Xeniidae (Octocorallia, Alcyonacea).- Sperm morphology of scleractinians from the Caribbean.- Embryonic and larval development of the sea anemone Haliplanella lineata from Japan.- Developmental pathways of anthozoans.- The life cycle of Laodicea indica (Laodiceidae, Leptomedusae, Cnidaria).- Notes on the morphology, ecology and life cyles of Fukaurahydra anthoformis and Hataia parva (Hydrozoa, Athecata).- The ampullae and medusae of the calcareous hydrozoan Millepora complanata.- Observations on the anatomy, behaviour, reproduction and life cycle of the cubozoan Carybdea sivickisi.- Distributional ecology and behaviour of the early life stages of the box-jellyfish Chironex fleckeri.- Oocyte development in four species of scyphomedusa in the northern Adriatic Sea.- Reproduction of Pelagia noctiluca in the central and northern Adriatic Sea.- IV. Ecology.- The growth patterns of some hydroids that are obligate epiphytes of seagrass leaves.- The growth and degeneration of the hydroid Sertularia perpusilla, an obligate epiphyte of leaves of the seagrass Posidonia oceanica.- The settlement and growth of Sertularia cupressina (Hydrozoa, Sertulariidae) in Langstone Harbour, Hampshire, UK.- Abundance and distribution of hydroids in a mangrove ecosystem at Twin Cays, Belize, Central America.- The adaptive pattern of growth and reproduction of the colonial hydroid Clavopsella michaeli.- Fission and the dynamics of genets and ramets in clonal cnidarian populations.- Distribution and adaptive strategies of alcyonacean corals in Nanwan Bay, Taiwan.- Effects of water movement on prey capture and distribution of reef corals [synopsis only].- How many damaged corals in Red Sea reef systems? A quantitative survey.- The effects of Acanthaster planci predation on populations of two species of massive coral.- Locomotion, asexual reproduction, and killing of corals by the corallimorpharian Corynactis califor-nica.- Comparative ecology of subtidal actiniarians from the coasts of California and the Gulf of Maine, USA.- Coral-crab association: a compact domain of a multilevel trophic system.- The symbiotic relationship between the hydrocoral Millepora dichotoma and the barnacle Savignium milleporum.- Chemical recognition by hermit crabs of their symbiotic sea anemones and a predatory octopus.- Mutualism between the antipatharian Antipathes fiordensis and the ophiuroid Astrobrachion constrictum in New Zealand fiords.- Predation on Cnidaria by vertebrates other than fishes.- V. Pelagic Coelenterates.- Western Atlantic midwater hydrozoan and scyphozoan medusae: in situ studies using manned submersibles.- Swimming movements of ctenophores, and the mechanics of propulsion by ctene rows.- Co-occurrence of hippopodiid siphonophores and their potential prey.- A review of cnidarians and ctenophores feeding on competitors in the plankton.- The role of prey stratification in the predation pressure by the cydippid ctenophore Mertensia ovum in the Barents Sea.- Hydromedusae of the Mediterranean Sea.- Vertical distribution of epipelagic siphonophores at the confluence between Benguela waters and the Angola Current over 48 hours.- Attraction of Aurelia and Aequorea to prey.- VI. Endosymbiosis.- Amino acids as a nitrogen source for Chlorella symbiotic with green hydra.- A review of some physiological and evolutionary aspects of body size and bud size of Hydra.- The stable level of coral primary production in a wide light range.- Mechanisms of amplification of photosynthetically active radiation in the symbiotic deep-water coral Leptoseris fragilis.- VII. Skeletogenesis.- The nature of the skeleton and skeletogenic tissues in the Cnidaria.- Chemistry and structure of skeletal growth rings in the black coral Antipathes fiordensis (Cnidaria, Antipatharia).- VIII. Palaeontology.- Principles of early ontogeny in the rugose corals: a critical review.- The Bainbridgia-Dualipora association (Cnidaria, Tabulata): palaeogeographical and palaeo-ecological implications.- IX. Evolution and Systematics.- Crossing-experiments between Japanese populations of three hydrozoans symbiotic with bivalves.- The variation of Halocordyle disticha (Cnidaria, Athecata) from the Brazilian coast: an environmen- tal indicator species?.- Samuraia tabularasa gen. nov., sp. nov. (Cnidaria, Hydrozoa, Hydrocorynidae), an intertidal hydroid from the Gulf of California, Mexico.- A jellyfish-eating sea anemone (Cnidaria, Actiniaria) from Palau: Entacmaea medusivora sp. nov..- Taxonomic characters from the polyp tubes of coronate medusae (Scyphozoa, Coronatae).- Morphological differences between, and reproductive isolation of, two populations of the jellyfish Cyanea in Long Island Sound, USA.- X. Biogeography.- The benthic deep-water siphonophore Rhodalia miranda and other coelenterates in the south-west Atlantic: ecological and oceanographical implications.- Hydromedusan distribution patterns.- Siphonophores of upwelling areas of the Campeche Bank and the Mexican Caribbean Sea.- XI. Genetics.- Dead-end evolution of the Cnidaria as deduced from 5S ribosomal RNA sequences.- Relationships within the family Actiniidae (Cnidaria, Actiniaria) based on molecular characters.- The heat shock response in hydra: immunological relationship of hsp60, the major heat shock protein of Hydra vulgaris, to the ubiquitous hsp70 family.- Effects of asexual reproduction on population structure of Sagartia elegans (Anthozoa, Actiniaria).- Gonad development of the sea anemone Anthopleura asiatica in clonal populations.- Experimental habituation of aggression in the sea anemone Actinia equina.- Acrorhagi, catch tentacles and sweeper tentacles: a synopsis of ‘aggression’ of actiniarian and scleractinian Cnidaria.- XII. Physiology and behaviour.- Monoamine concentrations in Hydra magnipapillata.- Neuropeptides in coelenterates: a review.- Peptides in the Hydrozoa: are they transmitters?.- Observations on bioluminescence in some deep-water anthozoans.- Propagation of bioluminescence in Euphysa japonica hydromedusae (Tubulariidae).- Interaction between the effects of light pulses of different chromatic content on Hydra attenuata and H. magnipapillata.- The physiological control of feeding in corals: a review.- The senses of sea anemones: responses of the SSI nerve net to chemical and mechanical stimuli.- XIII. Nematocysts.- Nematocysts of the Mediterranean hydroid Halocordyle disticha.- A comparative analysis of nematocysts in Pelagia noctiluca and Rhizostoma pulmo from the North Adriatic Sea.- Differentiation and ultrastructure of nematocysts in Halammohydra intermedia (Hydrozoa, Cnidaria).- Clinical manifestations of jellyfish envenomation.- Cubozoan jellyfish envenomation syndromes and their medical treatment in northern Australia.- Envenomation by the box-jellyfish Chironex fleckeri: how nematocysts discharge.- Cnida discharge and the mechanism of venom delivery in Anemonia viridis (Cnidaria, Actiniaria).- Effects of controlled treatment with trypsin on the functional characteristics of isolated nematocysts of Calliactis parasitica and Aiptasia mutabilis (Cnidaria, Actiniaria).- The spatial distribution of cations in nematocytes of Hydra vulgaris.- Discharge of nematocysts isolated from aeolid nudibranchs.- The differentiation of cytoskeletal structures in nematocytes of Hydra.- Remodelling during the development of nematocysts in a siphonophore.- Nematocysts of sea anemones (Actiniaria, Ceriantharia and Corallimorpharia: Cnidaria): nomen- clature.- Titles of presentations given during the conference but not included in the Proceedings.- Author index.- Taxonomic index.