Euspongia (Phylum-Porifera): Digestive system is absent. Fasciola (Phylum-Platyhelminthes): Digestive system is incomplete. Hydra (Phylum-Coelenterata): Digestive system is incomplete. Ancylostoma (Phylum-Aschelminthes): Digestive system is complete. Hirudinaria (Phylum-Annelida): Digestive system is complete.
