REVISION OF SOUTHWEST PACIFIC POLYMASTIIDAE (PORIFERA, DEMOSPONGIAE, HADROMERIDA) WITH DESCRIPTIONS OF NEW SPECIES OF POLYMASTIA BOWERBANK,TYLEXOCLADUS TOPSENT, AND ACANTHOPOLYMASTIA GEN. NOV. FROM NEW-ZEALAND AND THE NORFOLK RIDGE, NEW-CALEDONIA

Specific diagnostic characters are reviewed and redefined for the genu s Polymastia in northern New Zealand waters, to provide a framework fo r the recognition of new species, and for the revision and redefinitio n of other Polymastiidae. Eight new species of Polymastia are describe d, and Polymastia fusca Bergquist, P. hirsuta Berquist, and P. cf. mas silis Carter are redescribed in the light of new material. Species of Polymastia which contain exotyles and centrotylote oxea in addition to the usual megasclere complement, provided the opportunity to redefine the polymastid genera Proteleia, and Tylexocladus, which would typica lly have been reserved respectively, for sponges with these spicules. A new species of Tylexocladus is described from the Chatham Rise in so uthern New Zealand, providing a first record of the genus from this lo cation. A new genus Acanthopolymastia is established for southern ocea n Polymastiidae with acanthose centrotylote oxea, with Atergia acantho xa Koltun from Antarctica as the type species. Two additional species from New Zealand and the Norfolk Ridge, New Caledonia are described, a nd all are compared to Atlantic species of the same genera. Suggestion s for partitioning of shallow-water Polymastia species are put forward .