Tabula (plur. tabulae): Transverse porous partition linking both walls of a two-walled cup.
Simple: Circular perforation.
Slitlike: Elongate elliptical shaped.
Pecten: Thin-tooth comb (with rods) structure.
Divided pore: Pores irregularly divided by radial protrusions of lintels.
Irregular: No geometrical pattern.