Zone A: Intervallum side.
Canal: Pore modified by skeletal structure thikening or by lintels streching. Canal length is greater than perforation diameter.
Lintel: Skeletal structure separating and bounding adjacent pores.
Intersept: Part of a wall or intervallum between two adjacent radial vertical structures (septa, taeniaeā¦).
Carcass: Part of wall on intervallum side.
IW: Inner wall.
Stirrup: Perforation in front of each vertical intervalar structure.
NB: Transverse section resembles stirrup.
Vertical intervallar structures: Longitudinal and often radial structures inside the intervallum (septa, taeniaeā¦).
Carcass perforations: inner wall (IW) | |_ Relationship between carcass canals zone A and intersept (IW)