The thin membranous structure between the two heart atria or the thick muscular structure between the two heart ventricles.
Comment:
[taxon-note] "'Terrestrial vertebrates have divided hearts in which septae separate the oxygenated and deoxygenated blood within the pulmonary and systemic circulations'"
Synonyms:
exact_synonym:
cardiac septa; heart septa; heart septum; septum of heart