Canad. Jour. Zool. 67: 2107-2119. 2 tabs. 18 figs.

–Engl. summ. Examination of bone samples from various parts of the dugong skeleton showed that the increased bone volume is due to hyperostosis of the periosteal cortices, whereas the increased bone density is due to greater compactness and mineralization of the tissue. These effects are localized in the head and thorax. The increased compactness is due mainly to decrease of osteoclastic bone resorption and to endosteal deposits which fill the medullary regions. Possible endocrine controls on these processes are discussed. Pachyostosis in the dugong is considered adaptive rather than pathological.