Page:Popular Science Monthly Volume 20.djvu/472

456 body; and their form has given to this class the scientific name Lamellibranchiata—plate-gills. The water bathing the gills is constantly renewed by means of cilia. "Wonderful, indeed, is the elaborate mechanism employed to effect the double purpose of renewing the respired



fluid and feeding the helpless inhabitants of these shells. Every filament of the gill-fringe, examined under a powerful microscope, is found to be covered with countless cilia, in constant vibration, causing, by their united efforts, powerful and rapid currents. ... So energetic,



indeed, is this ciliary movement over the entire extent of the branchial organs that, if any portion of the gills be cut off with a pair of scissors, it immediately swims away, and continues to row itself in