Land-worms | 20. Drilomorpha | Lumbricus Annelida { 21. Mailed worms | 21. Phracthelminthes | Crossopodia { 22. Bristle-footed | 22. Chætopoda | Aphrodite { worms | | ---------------------------------------------------------------- Chætopoda | Drilomorpha | | \-------v-------/ | Phracthelminthes | | | Echiurida| | Hirudinea Sipunculida | | | | | | | | | Onychophora \----v---/ | | | | +Gephyrea+ | | | | Arctisca | | | | | | | | | | \--v-—/ Chætognatha | \--v-----/ | | | | | \-----v-----/ Nematoda | | | | | | | \---------v---------/ \--v--/ | +Annelida+ | Acantho- | | | cephala | Stelmopoda | | | | | | Enteropneusta \--v--/ | | | | +Nemathelminthes+ | Lophopoda | Ascidia | | | +Bryozoa+ | Thalicea | | Nemertina | | | | | | | | | | | +Rotifera+ | | | | | | | | | | | | \---v-/ | | | | | | | +Rhynchocœla+ | | | | | \--v---/ | | | | \----v---/ +Tunicata+ | | | | | | | \-----------------------v-----------------------------/ +Cœlomati+ (_worms with body-cavity_) | Cestoda | | | | | Trematoda | | | | | Turbellaria | +Platyhelminthes+ | | | | | \-------v---------/ +Acœlomi+ (_worms without body-cavity_) | | Archelminthes +Prothelmis+ | | +Gastræa+