The primary bone of the cortex of the large sauropodhumerus from the Late Triassic of Thailand consistsentirely of laminar fibro-lamellar bone tissue (Fig.2 ).Growth marks are not very well developed, as there areneither LAGs nor polish lines but only modulations.The modulations are more closely spaced in the outercortex than in the inner cortex.The inner cortex showsresorption cavities and incipient secondary osteons butno secondary bone.The medullary cavity is small andcompletely filled with cancellous bone.