Two new species of Clathrina (Porifera, Calcarea) from the Norwegian coast

Two new species of Porifera belonging to the genus Clathrina Gray, 1867 hav e been described. Clathrina septentrionalis sp. nov. is described from Lang fjorden, northern Norway. The main diagnostic features of this new species are the massive and well-delimited cormus with prominent oscula, and a skel eton composed of triactines and tetractines with cylindrical actines and bl unt end. The species seem to have a wide distribution in the N.E. Atlantic. Clathrina cribrata sp. nov, is described from Kristiansund, western Norway and is diagnosed by a skeleton composed of triactines, where the actines a re slightly undulated, cylindrical, with blunt ends. Another good character is a sieve of cells below the osculum. The species is only known from the Norwegian coast.