Oceanic islands are islands that have always been islands, a definition that seems tautological until we compare it with some other land masses that may be termed 'islands.' Geology teaches us in fact that from the point of view of their origin islands may be divided into two quite sharply contrasted classes. There are those detached land masses usually lying near to or comparatively near to some continent, which have been in the course of time detached by the action of the waves from that continent, such as for instance the British Isles, which undoubtedly represent a portion of the European continent which was once quite continuous with Europe. On the other hand we have the Hawaiian archipelago, St Helena, Fernando Noronha, and other similar islands, which are more remote in their position from continents and concerning which it seems clear that they have originated _de novo_ by the action of submarine volcanos or of the growth of coral, combined with subsidence, following elevation, or from several of the causes combined. In any case the islands which are termed oceanic islands have never formed part of a continent. They are not relics of previously existing continents. It becomes a matter of great interest to compare the earthworms which are to be found upon oceanic islands with those which inhabit continental islands. Fortunately there are a good many facts at our disposal for this purpose; and we shall compare the earthworms of the Hawaiian archipelago with those which are found upon certain small islands lying to the south of New Zealand, viz. Campbell and Auckland islands and the more southern Macquarie islands. The earthworms of the Hawaiian archipelago have been studied by a good many persons, and altogether a number of species have been described from that group of islands of which the following is a list: _Pheretima hawayana_, _P. heterochaeta_, _P. peregrina_, _P. schmardae_, _P. hesperidum_, _P. morrisi_, _P. perkinsi_, _P. biserialis_ (= _P. elongata_), _Allolobophora putris_ (= Kinberg's _Hypogaeon havaicum_), _A. foetida_, _A. caliginosa_, _A. nordenskiöldi_, _A. limicola_, _A. rosea_, and finally the well-known _Pontoscolex corethrurus_. Of these species there is only one which is even possibly a form limited to the Sandwich Islands, and that is _Pheretima perkinsi_, a species which I myself at first described as a new form, but which was afterwards regarded as identical with _P. heterochaeta_ by Michaelsen, and later still resuscitated by Ude. All the others are found in many parts of the world and not only in the nearest mainland to the archipelago which we are now considering. I have had already occasion to speak of some of them as peregrine forms, especially of _Pontoscolex corethrurus_ which occurs all over the world.