A spiral valve, also known as the cochleariform process or twisting pouch, is a unique anatomical structure found in certain aquatic animals. This coiled tube, resembling a spiral staircase, serves a variety of vital functions for these creatures. Synonyms for the term "spiral valve" include "cochleariform apparatus" and "gyre coil". The spiral valve plays a crucial role in increasing surface area for nutrient absorption and aiding in digestion for these aquatic species. Its intricate design allows for more efficient absorption of nutrients, enabling these animals to thrive in their aquatic habitats. Hence, the synonyms highlight the significance and complexity of this extraordinary anatomical feature.