The other name for Platyhelminthes is flatwarms. These soft-bodied, bilaterally symmetrical, invertebrate animals have an incomplete digestive system. They have muscular and excretory systems. The muscular system allows them to move from place to place over solid surfaces, while the excretory system lets them maintain a proper balance of water and salts.Flatworms have shuckers for feeding and they absorb nutrients directly from the host’s digestive system with their shuckers.