In his paper "Versuch einer monographie der Gattung Pentastoma" (Ann. Wien Mus. Naturges. 1836, 1–32), he was the first to establish the distinct nature of the Pentastomida, placing them in a new group which he called Acanthotheca.
Heymons actively studied tongue worms (Pentastomida) and his collection of these animals is held in the Museum für Naturkunde Berlin.