. The Biological bulletin. Biology; Zoology; Marine biology. SIZE AND GROWTH IN A REEF CORAL 425 areolata is adapted for life on unstable substrates where it is constantly exposed to the danger of burial by shifting sediments, or to being overturned by wave turbulence and currents. The species has a very efficient mechanism for ridding itself of sediment by means of flagellar currents and moving sheets of mucus. It is also one of the few corals possessing a well developed righting reaction. We have observed colonies weighing up to about 65 grams successfully right themselves after having been
. The Biological bulletin. Biology; Zoology; Marine biology. SIZE AND GROWTH IN A REEF CORAL 425 areolata is adapted for life on unstable substrates where it is constantly exposed to the danger of burial by shifting sediments, or to being overturned by wave turbulence and currents. The species has a very efficient mechanism for ridding itself of sediment by means of flagellar currents and moving sheets of mucus. It is also one of the few corals possessing a well developed righting reaction. We have observed colonies weighing up to about 65 grams successfully right themselves after having been turned upside down. This was accomplished by a great swelling. Figure 3. Relation between size and development of surface convolutions in a growth series of the coral Manicina areolata. The dry weights of these specimens are gm., gm., gm., gm., gm., gm., and 117 gm., respectively. The smallest individual shown here has a simple cup shape and only one stomodeum. Proliferation of additional stomodea by intratentacular budding at first produces linear elongation of the theca; later this becomes gradually more complex by formation of folds and branchings. Eventually, the typical convoluted brain-like surface pattern seen in the largest specimen is achieved. The continuous valleys of the specimens shown indicate that they are all clones descended from single planulae. Colonies of M. areolata which are formed through fusion of more than one planula invariably have a corresponding number of separate and distinct valley systems. of the coenosarc through imbibition of water which was then vigorously ejected from the stomodea in the form of jets directed against the sand, thus undermining the colony on one side and rocking it until it was gradually righted in the normal position (Goreau, unpublished observations). It is almost certain that the ability of this coral to cleanse itself of sediment and to right itself if overturned must depend on its having a lar
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