Milleporina (millepores; massive hydrocorals; class Hydrozoa) Order of reef-forming Cnidaria whose members build massive, calcareous exoskeletons which have pores through which the polyps protrude. Milleporina are known from the Upper Cretaceous to Recent. See also STYLASTERINA.

Milleporina (massive hydrocorals, millepores; phylum Cnidaria, class Hydrozoa) An order of cnidarians whose members build massive, calcareous exoskeletons, which have pores through which the polyps protrude. The medusae are free but degenerate and are formed in special cavities. Milleporina are known from the Upper Cretaceous to the present.