Haeckel
Medullary shell single, composed of bars that define a small cube (cubical medullary shell); cortical shell a spongy meshwork arising immediately from the medullary shell, supported by many large, 3-bladed spines that protrude outside of the spongy mass. Cortical shell diameter without spines: 150-200 µm.
Ref.: Haeckel (1887).