Sixty two species of sponges, belonging to the Tetraxonia, of this number, 19 new ones: Brochodora latiramea n.sp., Pachypoterion biedai n.sp., Homalodora skrainivensis n.sp., H. polonica n.sp., H. brachiramosa n.sp., Heterostinia phytoniformis n.sp., Heloraphinia chordata n.sp., Phymatella irregularis n.sp., Thecosiphonia gracilis n.sp., Kozlowskispongia bulbosa n.gen., n.sp., Phyllodermia magna n.sp., Ph. pulchra n.sp., Eustrobilus extraneus n.sp., Ragadinia foraminifera n.sp., Plinthosella elegans n.sp., Acrochordonia regularis n.sp. and A. bifurcata n.sp. are
described and one new genus, Kozlowskispongia n.gen., is erected. The species investigated belong to Tetractinellida (2 species), Tetracladina (32 species), Megacladina (16 species) and Dicranocladina (7 species). In most species, the morphology of the body, the structure of the skeleton and the morphology of the megascleres have been studied. In many of them, the microscleres have been found.