Corallines

Corallines, or Nullipores, the family Corallinaceae among the Florideae or Red Algae, are distinguished by being thickly incrusted with carbonate of lime, which gives them considerable likeness to true coral. Their reproductive structures, both sexual and asexual, are in conceptacles sunk in the thallus, but with an opening to the surface at their apex. The chief genera are Corallina and Melobesia, and, though more abundant in warmer seas, they are represented on our coasts. Corallines to some extent protect rocks from denudation, and their remains, ground down by waves and blown by wind, form the "calcareous sand" of the Bahamas and Bermuda, which is in places cemented by percolating land-springs into a compact limestone.