Observations on Trichosphaerium platyxyrum sp. n.

SYNOPSIS. Trichosphaerium platyxyrum sp. n., a marine testate rhizopod, is described. The schizont is ∼ 67 /μm in diameter, sheathed with a membranous test of fibrils and matrix covered with thin, straight, blade‐shaped calcitic spicules. The gamont is ∼ 63 μm in diameter with a membranous test devoid of spicules. The tests of both stages contain circular apertures through which extend short dactylopodia. Locomotion is by lobopodia. Both the schizont and gamont are multinucleate with a mean of 38 nuclei/schizont and 23/gamont. Observed reproduction in both is by binary fission with variations described for the gamont. The type locality is the reef flat of Heron Island, Great Barrier Reef, Australia. It is suggested, but not confirmed, that Schaudinn's description of the life cycle of Trichosphaerium sieboldi may be extended to other species of Trichosphaerium.