Shallow-water Niphatidae (Haplosclerina, Haplosclerida, Demospongiae) from the São Sebastião Channel and its environs (tropical southwestern Atlantic),

Two niphatids are described here: Amphimedon viridis and Pachychalina alcaloidifera sp. nov. Amphimedon viridis is a common and conspicuous species in most of the tropical western Atlantic. Pachychalina alcaloidifera sp. nov. has this far been found only in the coasts of Rio de Janeiro and São Paulo states. Both species are described on the basis of series of specimens observed alive.