In the older literature this area is referred to as the pseudoraphe when applied to the araphid diatoms. Raphe type where raphe opens into a channel or canal. Internal openings of canal are called portules. Unornamented are in the central or middle part of the valve face. Area between internal proximal raphe ends, usually thickened.
Central nodule expanded to valve mantle is termed a stauros.
Apically-oriented costa which may or may not be perforated by raphe slit. Central sternum not perforated by raphe slit has previously been termed a pseudoraphe. All elements of the girdle region. Thickened bands or ribs. May be oriented apically or transapically.