Situated between septa or partitions.
- ‘Flanks of septa near interseptal spaces have higher, but more irregular, concentrations of Mg.’
- ‘Adult tabularial surfaces very gently convex, or slightly depressed periaxially, downturned in interseptal loculi and deeply depressed in cardinal siphonofossula.’
- ‘Septal margins show conspicuous zones of irregular dissolution around interseptal spaces, but the zones do not occur where septa grew together.’
- ‘In early stages, Eurekaphyllum is distinguished from Papiliophyllum by its calicinal expansions, tabulae which are not domed eccentrically in the counter quadrants, and by its commonly open cardinal interseptal loculi.’
- ‘Thin sclerenchyme covers some tabularial surfaces, especially those in the siphonofossula and peripheral interseptal depressions.’