Descriptor : Direction of carcass canals (OW/SW)

Descriptor type : categorical

NB: Convention: Tube begins on 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.

OW: Outer wall.

SW: Single wall.

Carcass: Part of wall on intervallum side.

Upwardly opening

Upwardly opening: Opening on intervallum side is lower down than the other one.

Downwardly opening

Downwardly opening: Opening on intervallum side is higher than the other one.

Horizontal opening

Horizontal opening: Opening on intervallum side is as high as the other one.

isn't included in the term

Hierarchy

Carcass perforations: outer wall or single wall (OW/SW)
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 |_ Direction of carcass canals (OW/SW)