exer 6

• A eucoelomate, also known as a coelomate, is an animal with a true coelom, which is a fluid-filled body cavity that surrounds the gut
• Coelom: A fluid-filled space between the body wall and the visceral organs that contains the digestive system, heart, kidneys, reproductive organs, and circulatory system.
• Peritoneum: A complete lining of the coelom that attaches to organs.
• Mesoderm: The germ layer that gives rise to the peritoneum. 
• Pseudocoelomate metazoans have a fluid-filled body cavity, which, unlike a true coelom, does not have a cellular peritoneal lining.
• Class Turbellaria: All free-living; body covered with ciliated epidermis containing secreting cells; mostly hermaphroditic. Ex. Dugesia (planaria).
• Class Monogenea: Monogenetic flukes; all parasitic on the skin or scales of fishes. Ex. Polystoma
• Class Trematoda: Digenetic flukes; all parasitic on man and domestic animals. Suckers and sometimes hooks are present; the digestive system is gastrovascular type, usually with two main branches. Ex. Blood fluke- Schistosoma japonicum; Lung fluke- Pargonimus westermanni Liver fluke- Fasciola hepatica; Clonorchis sinensis
• Class Cestoda: All parasitic tapeworms; suckers or hooks present; digestive system absent. Ex. Beef tapeworm- Taeniaryhncus saginatus; Pork tapeworm- Taena solium
• Class Rhabditae: Amphids ventrally coiled, three esophageal glands, some with a pair of minute sensory pouches (phasmids) near the posterior tip.
• Class Enoplea: Phasmid lacking; amphids usually well-developed