"Echinus gracilis. a, ambulacral plates; b, poriferous zone; c, interambulacral plates." — Encyclopedia…
An 8-inch sphere cut by parallel planes, one 2 inches from center and the other 6 inches from center.…
An illustration of a zone of a sphere. A zone occurs when a sphere is cut by parallel planes that are…
An illustration of a zone of a sphere. A zone occurs when a sphere is cut by parallel planes that are…