The Digestive Apparatus of a Hydra or Freshwater Polyp
In Radiata the digestive cavity is a pouch with a single opening, into which the food is passed and from which the residuum is ejected, as in the Hydra.
GalleriesCorals and Sea Anemone
Cutter, Calvin First Book on Analytic Anatomy, Physiology and Hygiene, Human and Comparative (Philadelphia: J. B. Lippincott & Co., 1875) 72