Platyhelminthes is a type of animal with bilateral symmetry, three germ layers, no body cavity, no respiratory system, no circulatory system, and a mouth but no anus. There are approximately 15,000 recorded species of Platyhelminthes. It lives in moist places such as fresh water and oceans, and has two photosensitive pigment spots on the front of its body. Part or all of the body surface is covered with cilia. Most species live a parasitic life (such as schistosomiasis, tapeworms, and Clonorchis