Intervallar cell: Part of intervallum bounded by adjacent radial-longitudinal partitions and tangential synapticulae.
Intervallum: Space enclosed between the walls.
Synapticula (plur. synapticulae): Narrow horizontal rod linking two adjacent vertical intervallar structures.
Calicle: Longitudinal tubelike intervallar structure, which can be hexagonal or tetragonal in cross-section.
Syrinx (plur. syringes): Intervallar structure comprising porous radial horizontal or curved tube with hexagonal or tetragonal cross-section.
Intervallum: Space enclosed between the walls.
Presence of intervallar cells | |_ Type of Intervallar cells {None} | |_ Section shape of intervallar cells {None} | |_ Number of pores rows per facet (intervallar cells) {None}