A genus of extinct calcareous red algae (Rhodo­phyta). Solenopora is characterized by encrusting, rounded, nodular growth forms ranging in size from several millimeters to a few centimeters. Internally, this alga consists of calcified rows or filaments of cells, commonly polygonal in shape, ranging from 20 to 100 micrometers in diameter. Although the cellular tissue is similar to modern coralline algae, the cells in Solenopora are generally larger and are not differentiated into more than one kind of cellular arrangement.