The cerebellum is well developed and possesses large floccular lobes composed mainly of the paraflocculus, probably associated with pronounced swimming and equilibratory activities (Harrison & King, 1%5). Native dugong hunters consider that the hearing of dugongs is acute but that their visual powers are less developed (Prater,1929; Jarman, 1966; Roughsey, 1971). The unusual arrangement of the ear ossicles has been described by Robineau (1%5) and their vibrations measured by Fleischer (1971).