English: "Morphology of the Chlamydosaurus frill and associated hyoid apparatus. (A) Erected and (B) folded frill of a juvenile (11 months old) frilled dragon. The left and right lobes of the frill each presents 3 pairs of convex ridges (cyan lines), two pairs of valley folds (green lines); the two lobes are joined at a central crease (white line). (C) The CBI + EB and ‘Grey’s cartilage’ (yellow line in A) are embedded in the third convex ridge (cyan star in A) and the dorsal side of the frill, respectively. (D) Adult hyoid apparatus treated with alcian blue (staining cartilage) and alizarin red (staining bone). ‘EP’: entoglossal process, ‘HH’: hypohyal, ‘CH’: ceratohyal, ‘EH’: epihyal, ‘CBI’: ceratobranchial I, ‘EB’: epibranchial, ‘CBII’: ceratobranchial II. The central and anterior parts of the hyoid apparatus and first pair of horns (HH +CH + EH) originate from the second branchial arch (BA2), whereas the second (CBI + EB) and third (CBII) horns originate from the BA3 and BA4, respectively. (E) CT scan of an adult female (yellow, hyoid apparatus; red, skull and vertebrae); dashed lines indicate the approximate position of histological sections..."