General features The tegument is a syncytial layer equipped with spines and muscles a Digestive system degenerated with a mouth, enclosed by the oral sucker but no anus mouth→ pharynx→ esophagus→ two digestive tracts u Hermaphrodite or monoecious except blood flukes (dimorphism), possessing both male and female reproductive organs, the appearance and position of which are very important taxonomically◼ The tegument is a syncytial layer equipped with spines and muscles ◼ Digestive system degenerated， with a mouth, enclosed by the oral sucker but no anus. mouth→pharynx →esophagus → two digestive tracts ◼ Hermaphrodite or monoecious except blood flukes (dimorphism) , possessing both male and female reproductive organs, the appearance and position of which are very important taxonomically General features