Development of the neo-morphic air breathing organ in the swamp-eel, Monopterus albus (Zuiew).

The embryonic gill material derived from the 1st gill arch gives rise to the respiratory epithelium of the mouth cavity for aerial respiration in Monopterus albus. A comprehensive gill mass formed by mixing of the embryonic gill materials derived from the dorsal ends of the gill arches (II to V) gives rise to the fused gill filaments on the 1st and IInd gill arches that subserve the purpose of utilizing O2 from air or water.