External gills

Instead, the respiratory organs are set on a frill of stalks protruding from the sides of an animal's head.

This type of gill is most commonly observed on the aquatic larva of most species of salamanders, lungfish, and bichirs (which have only one large pair), and are retained by neotenic adult salamanders and some species of adult lungfish.

Fossils of the distant relatives of modern amphibians, such as Branchiosaurus and Apateon, also show evidence of external gills.

The stalk usually contains muscle tissue, and may be moved by the animal as a free appendage, in order to stir up stagnant water.

The stalk is lined by many thinly walled filaments (fimbriae), containing the majority of blood vessels used in gas exchange.