AGE-ESTIMATION OF THE CHRISTMAS-TREE-WORM SPIROBRANCHUS-GIGANTEUS (POLYCHAETA, SERPULIDAE) LIVING BURIED IN THE CORAL SKELETON FROM THE CORAL-GROWTH BAND OF THE HOST CORAL

The tubicolous polychaete, Spirobranchus giganteus lives buried in cor al skeletons. Its age and longevity were estimated indirectly from the annual coral-growth rings of the host coral counted on soft X-rays ra diographs. Since the polychaete tube grows 0.2 to 1 mm per year in ori fice diameter, some had lived more than 10 years, and a few had lived more than 40 years. The application of soft X-rays for age determinati on of coral associated polychaete is useful for determining the correc t age.