Trematodes, general anatomy.1. oral sucker, 2. ventral sucker, 3. pharynx, 4. oesophagus, 5. intestine, 6. small excretory tubulus, 7. collection tube, 8. excretion bladder, 9. excretory pore, 10. testis, 11. and 12. vas deferens, 13. seminal vesicle, 14. prostate, 15. cirrus (ejaculation duct), 16. cirrus sac