REVISION OF GENERA AND SPECIES COMPOSITION OF LOWER CENTROHELIOZOA .2. FAMILY RAPHIDIOPHRYIDAE N FAM

A revision of the genus Raphidiophrys ARCHER On the basis of the scale structure is performed. Two new genera are proposed. Parasphaerastrum gen. nov. includes a single species, P. marina (OSTENFELD) emend. MIK RJUKOV, surrounded by the envelope of rod-like tangential siliceous sp icules. Polyplacocystis gen. nov. includes five species, two with reti culate [P. ambigua (PENARD) and P. symmetrica (PENARD)] and three with smooth [P. pallida (SCHULZE), P. marginata (SIEMENSMA) and P. peduncu lata (MIKRJUKOV)] surface of scales. Six other EM-studied species [R. capitata SIEMENSMA et ROIJACKERS, R. elegans HERTWIG et LESSER, R. int ermedia PENARD, R. minuta NICHOLLS, R. viridis ARCHER and R. ovalis (D URRSCHMIDT)], which have complex scales formed by two parallel plates and internal septae between them, are retained in the genus Raphidioph rys ARCHER. Only three species with plate-scales identical to those in Polyplacocystis (R. lemani PENARD, R. tubifera PENARD, and R. glabra NICHOLLS et DURRSCHMIDT) stay in the genus Raphidocystis with the emen ded diagnosis given by NICHOLLS & DURRSCHMIDT (1985). The new family R aphidiophryidae is proposed including the genera Parasphaerastrum, Pol yplacocystis, Raphidiophrys and Raphidocystis. A key for the species o f these genera is proposed.