Capite depresso; membrana tympani aperta. Gula pennulis plicatis ornata. Pedibus quatuor. Digitis quinque, elongatis, simplicibus. Cauda elongata, subcylindrica. Animal scaly; the head depressed; the nostrils placed on the side, midway between the eyes and the end of the head; the drum of the ear naked; the front teeth conical, awl-shaped (eight in the upper, and four in the lower jaw); the hinder ones largest; the side or cheek teeth compressed, short, forming a single ridge, gradually longer behind; tongue short, fleshy, with an oval smooth disk at each side of the lower part of its front part; neck rather long, furnished on each side with a large plaited frill, supported above by a crescent-shaped cartilage arising from the upper hinder part of the ear, and, in the middle, by an elongation of the side fork of the bone of the tongue; body compressed; legs rather long, especially the hinder ones; destitute of femoral pores; feet four, with five toes, the first having two, the second three, the third four, the fourth five, and the little finger and toe three joints; claws compressed, hooked; tail long, nearly round, scaly. This genus appears to be nearly allied to the Agamae, but differs from them in the peculiar frill that is appended to the neck. 1. Chlamydosaurus kingii (n.s.) C. corpore luteo, nigro, variegato; squamis carinatis; pennula antice serrata; cauda corpore duplo longiore. Chlamydosaurus kingii, Gray manuscripts. Icon. Table A. Natural size. Inhabits Port Nelson, north-west coast of Australia.