MYZOSTOMES FROM PAPUA-NEW-GUINEA, WITH RELATED INDO-WEST PACIFIC DISTRIBUTION RECORDS AND DESCRIPTION OF 5 NEW SPECIES

Eighteen species of myzostomes were found in association with crinoids collected in Papua New Guinea. Thirteen of the former are described b y means of in vivo, light microscopical, and SEM-based observations. F ive are new to science: Myzostoma cuniculus, M. laingense, M. nigromac ulatum, and M. longitergum are ectocommensals; Contramyzostoma sphaera is a parasite living in a soft cyst induced upon its host. The eight previously described species, six of which are redescribed in detail, include Myzostoma ambiguum Graff, M. capitocutis Eeckhaut, VandenSpieg el and Grygier, M. fissum Graff, M. mortenseni (Jagersten), M. polycyc lus Atkins, and M. stochoeides Atkins, as well as Hypomyzostoma crossl andi (Boulenger) and Notopharyngoides aruensis (Remscheid). Most are e ctocommensals but the last is an intradigestive symbiont. New Indo-Wes t Pacific distribution and host records for all eight are listed, base d on surveys of museum collections, and their entire range are mapped. Hypomyzostoma Perrier, 1897 (type species Myzostoma folium Graff) is resurrected for one of the species-groups previously recognized within Myzostoma, and a lectotype is selected for H. crosslandi. Specimens f rom Singapore previously identified as M. elegans Graff are reassigned to M. capitocutis.