- according to Hottinger (2006):
SUPPLEMENTARY APERTURE (secondary aperture(s), pars. auct.) - primarily formed openings either in the apertural face ("apertural pores") or (slit-like) in a sutural position, always in addition to a main cameral aperture. Sutural supplementary apertures are not converted into intercameral foramina because of their position and thus apparently do not serve for passage of functional endoplasm between chambers. The same seems to be true of some multiple supplementary apertures, which - although situated in the septum - may be absent in earlier chambers and/or may be plugged in part at a subsequent instar.
Hottinger (2006), Illustrated glossary of terms used in foraminiferal research. Carnets de Géologie, Memoir 2, ISSN 1634-0744