flatworm found on a coral in saipan while diving

anatomy animal background biology bright cell cilia closeup coral diving excretory female flame flat flatworm found ganglia gastrovascular gonopore macro microscopic morphology nature nephridia nephridium nerves nervous ovary physiology planaria planarian platyhelminthes predator protonephridia protonephridium reproductive saipan schema scheme secretory seminal structure system testes tube turbellaria urinary vesicles water white worm zoology