Two new species and a new genus of scleractinian corals from the Red Sea are described. Merulina scheeri sp. nov. differs from M. ampliata in its larger calicinal structures, monocentric tendency and corallum form. Its distribution in the Port Sudan area suggests an ecological preference for deeper, sheltered reef slopes. Craterastrea levis gen. et sp. nov. is described as a new siderastreid coral, previously confused with Leptoseris. It has the septo-costal and thecal characteristics of the family Siderastreidae, but is generically isolated by its corallum form and sparse and non-excavated calices. It appears to be confined to depths in excess of 30 m on typical reef slopes.