The collection includes all multicellular animals not belonging to vertebrates, arthropods, molluscs or polychaetes. These include sponges, cnidarians, all worm-like groups (flatworms, roundworms, ringworms and others), echinoderms and tunicates. Parts of the collections are of international importance. First of all, there are the 4000 oligochaetae specimens, among them more than 1350 types, which have been used to re-describe a species. This means that about 16% of the type material for oligochaetes is in the Hamburg collection.