A survey of octocorals belonging to the family Xeniidae collected from the coral reefs of the Ryukyu Archipelago (Japan) revealed colonies with distinct scle-rites whose microstructure justifies the establishment of a new genus, Yamazatum. A new species, Y. iubatum has been assigned to it and is described and depicted. Its fea-tures include unique sclerites with previously undocu-mented surface architecture, comprising of one or several crests and occasionally one or several furrows, different-iating it from all known species of the family Xeniidae.

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Manoli Reef Complex (MRC) and Kurusadai Reef Complex (KRC) of the Gulf of Mannar, southeast coast of India were taken for this study to estimate the biophysical status of the coral reef ecosystems. This study was conducted between the years 2006 and 2008. About 25 sites all around the islands were chosen for this study. Among them, good Live Coral (LC) cover was recorded in fourteen sites. The other categories like Dead coral with algae, Exposed reef and Rubble, Seagrass, Algal assem-blage, Muddy flat and Sandy flat were also considered in this study. The estimated sedimentation rate of this area was higher in seaward sides than the shoreward sides.

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Planula larvae of the coral genus Acropora ini-tiate metamorphosis in response to microorganisms on the undersea substrate. Since planulae move forward in the direction of the aboral side, it is supposed that initial metamorphic signaling localizes on this side of planula. We dissected planulae of Acropora tenuis into fragments perpendicularly to the oral-aboral axis, and tested their response to a metamorphosis-inducing neuropeptide. Aboral 1/3 fragments metamorphosed in response to the neu-ropeptide with high efficiency while most oral 2/3 frag-ments did not. The results suggest that the tissue in the aboral 1/3 region receives the metamorphic neuropeptide and releases downstream signals to complete metamor-phosis of the oral side in A. tenuis larvae. In addition, oral fragments gained a metamorphic ability in several days, revealing regeneration of the aboral tissue.

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