Haeckel
Two concentric, spherical, latticed medullary shells and one spongy cortical shell. With large, 3-bladed spines with serrated edges originating in the second medullary shell and protruding conspicuously outside of the spongy outermost shell. Outer shell diameter without spines: ca. 300 µm.
Ref.: Hollande and Enjumet (1960).