rowth and form of marine organisms inhabiting hard substrata, the G"marine sessile organisms", ischaracterized by anumber ofremarkable properties. One remarkable feature of these organisms is that many ofthem can be characterizedasmodularorganisms. Modularorganisms are typically built ofrepeated units, the modules, which might be a polyp in a coral colony or afrond in seaweeds. In most cases, the modulehas adistinctive form, while the growth form...