Some articles on calcareous hard parts, calcareous:
... vulnerable marine organisms were those that produced calcareous hard parts (i.e ... and had low metabolic rates and weak respiratory systems—notably calcareous sponges, rugose and tabulate corals, calciate brachiopods, bryozoans, and echinoderms ... Close relatives without calcareous hard parts suffered only minor losses, for example sea anemones, from which modern corals evolved ...
Famous quotes containing the words parts and/or hard:
“It is now many years that men have resorted to the forest for fuel and the materials of the arts: the New Englander and the New Hollander, the Parisian and the Celt, the farmer and Robin Hood, Goody Blake and Harry Gill; in most parts of the world, the prince and the peasant, the scholar and the savage, equally require still a few sticks from the forest to warm them and cook their food. Neither could I do without them.”
—Henry David Thoreau (18171862)
“Truly man is a marvelously vain, diverse, and undulating object. It is hard to found any constant and uniform judgment on him.”
—Michel de Montaigne (15331592)