annuli may mutually coalesce

knowledge base : exist
structure : inner wall
Stipules : isn't included in the term
Carcass perforations: inner wall (IW) : isn't included in the term
Carcass external plates: inner carcass wall (IW) : Present
Type of carcass external plates (IW) : Annuli
Relationship between carcass annuli and tabulae (IW) : isn't included in the term
Shape of carcass external plates (IW) : Fused
Direction of carcass external plates (IW) : isn't included in the term
Type of morphological tubes (IW) : isn't included in the term
Additional sheath : isn't included in the term