ABSTRACT
Pearls have long been of economic importance as jewelry. Many shelled mollusks produce pearls, which are the animals’ means of excluding or walling off foreign bodies by secreting shell around them. The body and shell of the pearl oyster, Pinctada fucata, are asymmetrical. The shell is shaped like a horseshoe. The prismatic layer forms the major portion of the shell, and the nacreous layer is the inner pearly lining of the shell cavity. In the adult, effects of salinity on ciliary movement on the gills, heartbeat, mass of water filtered, disappearance of the crystalline style, and mortality were studied. Pinctada fucata is dioecious. The gonad surrounds the digestive diverticula, intestines, and retractor muscles. Sometimes, sexual change is observed between different spawning seasons, and protandry is observed in many cases. The eggs complete meiosis when fertilized, and the first and second polar bodies are extruded before the polar lobe extrudes.
