16 November 1973
Vol 182, Issue 4113

About The Cover

Three echinoids (Diadema antillarum) photographed at night at the edge of a halo surrounding a patch reef in the West Indies. Grazing by the echinoids results in the formation of halos. See page 715. [John C. Ogden, West Indies Laboratory, Fairleigh Dickinson University, St. Croix, Virgin Islands]