Fam. IV. MEGAPODIIDAE.–The Megapodes, or Mound-builders, commence the section Peristeropodes (p. 186) of the Sub-Order GALLI. The bill is short, stout, and arched, though rather slender in _Megapodius_; the feet are exceptionally strong, and enormous for the size of the birds, _Lipoa_ having the smallest; while the metatarsi are usually scutellated, but are reticulated anteriorly in _Megacephalon_, which has comparatively short and blunt claws. The abbreviated wings have ten primaries and some six secondaries. The tail is long and rounded in _Talegallus_ and _Lipoa_, with upper coverts extending to the tip in the latter; it is short but still rounded in _Megapodius_; long and obcordate when expanded in _Catheturus_, _Aepypodius_, and _Megacephalon_. The rectrices number twelve in _Megapodius_, sixteen in _Lipoa_, {191}_Talegallus_, and _Aepypodius_, eighteen in _Megacephalon_ and _Catheturus_. _Aepypodius_ possesses an erect fleshy frontal crest and a pendent caruncle at the base of the fore-neck, or even a pair of lateral outgrowths near the nape; _Catheturus_ has a vascular neck-wattle: and _Megacephalon_ a rounded bony casque with a tubercle behind each nostril. The fleshy growths are yellow or reddish, the horny black. In _Aepypodius_, _Catheturus_, and _Megacephalon_ the naked head is clothed with hair-like feathers or papillae; _Lipoa_ and some species of _Megapodius_ have a short dense crest; others have the head almost entirely feathered, others again nearly bare except the occipital and nuchal region, as in _Talegallus_. The naked skin may be red, yellow, orange, purplish, grey, or pale blue; the bill and feet are black, brown, olive, yellow, red, orange, horn- or parti-coloured. The furcula is Y-shaped, the syrinx tracheo-bronchial, the tongue sagittate, the gizzard muscular, and the aftershaft small. The size varies from that of a Turkey to that of a large Pigeon, the sexes being invariably similar.