TREPOSTOMATA

extinct order of bryozoans (moss animals) found as fossils in marine rocks of Ordovician to Triassic age (208 to 505 million years old). The trepostomes are characterized by colonies in long, curved calcareous tubes, the interiors of which are intersected by partitions. The order includes several common and well-known genera, including the Ordovician forms Prasopora and Dekayella.