Corals, jellyfish, gorgonians and anemones are cnidarians. These animals are characterised by the presence of urticant cells (or cnidoblasts). Present on their tentacles in large numbers, these urticant cells are used to paralyse their prey and for self-defence. Some cnidarians are dangerous to humans.


Presentation
The Muséum’s cnidarian collection has four groups: Hydrozoa, Octocorallia, Hexacorallia and all the Jellyfish.
The collection includes about 80,000 specimens preserved in jars of alcohol or dried, in histological slides and in herbaria for some hydroids and gorgonians. It includes old specimens from all the oceans. Part of the Scleractinia or hard coral collection is remarkable because the specimens are accompanied by field notes enabling us to situate them in their environments. This is the case with the specimens brought back by Jean-Pierre Chevalier, which enriched the collection until 1981. The collection of deep sea specimens is one of the biggest in the world and is growing all the time.

History
The oldest specimens (1706-1707) of Hydroids and Octocorallia in the collection are stored in herbaria created by Sébastien Vaillant.
The collection’s history can be read in the yellowed old labels, featuring such big names as Péron and Lesueur, Savigny, Jean-Baptiste de Lamarck, Quoy and Gaimard, Valenciennes, H. Milne-Edwards and Haime, who made their mark on science in this field.
Generations of scientists have contributed to enriching the collection, thanks to expeditions by naturalists such as the trip to Egypt (1800-1804), Baudin’s trip to the west coast of Australia, the Astrolabe expedition (1837-1840) and the two French Antarctic expeditions in the early 20th century. For around forty years, various campaigns in the Atlantic (Thalassa, Biogas, etc.), the sub-Antarctic (on the Marion-Dufresne) and the Indo-Pacific (MUSORSTOM/Deep-Sea Benthos programme) as well as major expeditions (Santo, Vanuatu 2006, Guadeloupe, 2012), some embarked on as part of the “Our Planet Reviewed” programme, have further enriched the collection.
Some scientists have donated collections assembled throughout their careers, for instance the collections of G. Faure, J. Laborel, M. Pichon, B. Salvat, H. Zibrowius… J. Goy’s harvests in the Mediterranean, Brazil and Australia further enhanced the Jellyfish collection.

Research
The cnidarian collection has applications in fundamental and applied research in the fields of systematics and biogeography. Coral skeletons provide a record of environmental parameters, so coral collections are of great interest in the fields of climatology and palaeoclimatology.
The historical collections are temporal series. They have enabled us to trace the frequency of invasions by the Pelagia noctiluca jellyfish in the Mediterranean over a 12-year period. They are an aid to museology, education and training.
The Scleractinia collections, listed in appendix II of the CITES, are also visited for educational purposes by agents in charge of enforcing the Washington Convention.
The Typotheque (group of types that are the reference specimens) of the Scleractinia, which contains over 500 specimens, is being reorganised. Access to it is limited. For all consultations, a request must be made on colhelper.
The data relating to the specimens are to be integrated into the databases, and in the case of metropolitan and overseas France, added to the Inventaire National du Patrimoine Naturel (INPN - National Inventory of the National Heritage).

Contact
Magalie Castelin, head of the collection
magalie.castelin [@]mnhn.fr