External plates: Plate covering incompletely one or several perforations of a wall.
Carcass: Part of wall on intervallum side.
IW: Inner wall.
Spine: Skeletal structure comprising a narrow, elongate and typically tapering process with a circular to subcircular attachment area.
NB: Spines resemble bracts.
Bract: Plate stems from lintels which incompletely covering a single pore.
Lintel: Skeletal structure separating and bounding adjacent pores/canals.
Bracts and structures similar to scales coexist.
Bract: Plate stems from lintels which incompletely covering a single pore.
Lintel: Skeletal structure separating and bounding adjacent pores/canals.
Fused: Adjacent bracts or scales of the same horizontal file are incompletely amalgamated to form a single structure covering two or more perforations of a wall.
NB: fused bracts resemble scales.
Bract: Plate stems from lintels which incompletely covering a single pore.
Lintel: Skeletal structure separating and bounding adjacent pores/canals.
Annulus (plur. annuli): Ring-shaped (annular) plate separating horizontal rows of pores.
Scale: Plate incompletely covering two or more adjacent pores or intersepts in the same horizontal file. They are intermediate between fused bract and annulus.
Scales and structures similar to annuli coexist.
Fused: Adjacent bracts or scales of the same horizontal file are incompletely amalgamated to form a single structure covering two or more perforations of a wall.
NB: fused scales resemble annuli
Annulus (plur. annuli): Ring-shaped (annular) plate separating horizontal rows of pores.
Annuli of different horizontal files may mutually coalesce.
Poretube: Structure of elongate, scooplike to tubular shape completely or almost completely covering a single pore.
NB: Poretubes resemble canals but have a bract origin.
Presence of carcass external plates: inner carcass wall (IW) | |_ Type of carcass external plates (IW) | |_ Localization of carcass bracts (IW) {Spines , Scales , Scales AND fused scales , Annuli , Annuli AND fused annuli , Poretubes} | |_ Shape of the interlocking of successive carcass annuli (IW) {Spines , Bracts , Bracts AND fused bracts , Scales , Poretubes} | |_ Localization of carcass annuli according tabulae (IW) {Spines , Bracts , Bracts AND fused bracts , Scales , Poretubes}