[From introduction:]
Since ''An annotated list of the pelagic Polychaeta'' was published in 1956 there have been a number of studies which have considerably extended our knowledge and which now make a review worthwhile. All the publications making reference to pelagic polychaetes of which we are aware have been included in the Bibliography. The species are numbered for easy reference, and under each species there is a complete synonymy, taxonomic comments wherever required, general distribution and location of the type when known. Some of the species, notably those belonging to the genera
Vanadis and
Tomopteris have never been rediscovered following their original description. Some of these may eventually prove to be synonyms of better known species. It is hoped that this synopsis will prove of use to plankton workers for it was compiled as an aid for further study. The synopsis lists the species belonging to the exclusively pelagic families Lopadorhynchidae, Iospilidae, Pontodoridae, Alciopidae, Tomopteridae and Typhloscolecidae only. There are, of course holopelagic species belonging to other families, and some forms normally benthonic which may sometimes be found in the plankton, especially inshore. Of these, the most frequent belong to the Polynoidae. Many are late larvae of benthonic forms; others such as
Dreishia pelagica and some
Macellicephala species may be truly holopelagic, but we know little about these species and much work remains to be done to distinguish those which are truly holopelagie from those that are merely late larvae of benthonic forms. Reference should be made to Fauvel (1914), Støp-Bowitz (1948), Knox (1959) and Tebble (1960) for information on these genera. Pettibone (1966) regards Chamberlin's (1919)
Podarmus ploa found off Easter Island as a pelagic form. The specimens described by Berkeley & Berkeley (1961) as
Ancistrosyllis longicirrata and by Støp-Bowitz (1948) and Monro (1930) are all apparently the same species,
Podarmus ploa, described by Chamberlin (Pettibone, 1966). Mileikovskii (1969) has recently described the larvae of
Lagisca hubrechti and of
Lepidasthenia grimaldi commonly found in plankton and possibly holopelagic forms. Many spioniform larvae have been described by Hannerz (1961). The curious
Poeobius meseres Heath is also easily recognized and is certaintly holopelagic. It has been studied in some detail by Robbins (1966). Reference to
Poeobius has also been made fairly recently by Hartman (1955), Berkeley & Berkeley (1960) and its distribution described by McGowan (1960). Hartman placed the Poeobiidae near the Flabelligeridae in which
Flota flabelligera recently discovered off Chile, belongs (Hartman, 1967). The Otopsidae are presumably benthonic. Berkeley & Berkeley (1957) found
Otopsis longipes Ditlevsen in open water, and earlier Berkeley (1956) found
Epidiopatra hupferiana Augener similarly in open water, but there is little doubt that these are benthonic worms. Ditlevsen (1917) did not describe how his specimen was collected, but Wesenberg-Lund (1950 a) stated that it was dredged. Uschakov (1955) has described a somewhat similar specimen (
Otopsis longipes pacifica) in the Sea of Okhotsk.
