The late Permian reefs are distributed in Chengxian

Guiyang and Chenxi Counties in southern Hunan province. Reefs in Bangxian and Guiyang are patch reefs developed along Chengru shallow sea. Reefs in Chenxi are bioherms

undeveloped patch reefs. The reefs in both sites occur in the late Permian Changxing Formation. A lot of samples of fossils and rocks have been collected while surveying 8 reef composite sections in southern Hunan. We find that the most important frame-building organisms are calcisponges

just as other Permian reefs in southern China. By systematically researching Inozoans

one of the important frame-building calcisponges

it is thought that the water system and fibres might be important evidence in classification. Twelve species and 8 genera of Inozoans including one new species

one comparative species and one undefined species are found

and some species are newly classified.