For Hydromedusae the coverage is worldwide through the Dana expeditions, and the collection comprises a large number of types (P. Kramp). The hydropolyp collection is very representative for the North Atlantic, and this is the case also for both main groups of Anthozoa. Large numbers of tropical octocorals (mostly undetermined) originate from the Th. Mortensen expeditions. From older times, the Hexacorallia, mostly from the Caribbean area, are richly represented, but provided only with scanty sampling information.
Current research: The taxonomy, zoogeography and relationships with other faunas of northern octocorals and scleractinians.