The Distribution and Evolution of Terrestrial Nemertines

The occurrence of terrestrial nemertines on widely separatedoceanic islands is described: there are three groups of species(in Australia, New Zealand and the Indopacific islands) andthree separate species on Atlantic islands. Parallel evolutionfrom separate marine ancestors is indicated. The evolutionaryrelationship between different species is established on securemorphological grounds, with particular reference to the genusPantinonemertes which comprises marine, semi-terrestrial andfully terrestrial species. The distribution of terrestrial nemertinesis discussed. Most species are extremely localised but a fewhave become widely dispersed, notably Argonemertes dendyi butalso Geonemertes pelaensis and to a lesser extent Leptonemerteschalicophora. At least two of these widespread species are hermaphrodite.