But whilst in Trematoda a digestive sac is invariably present except in the sporocyst larval stage, the Cestodes possess no trace of this organ at any stage of their development.
2
The generative organs are of the complex hermaphroditic type described in Trematoda (q.v.).
3
The only comparable fact among other worms is the Laurer's canal or genitointestinal canal in the Trematoda.