| Coelom |
Absent |
Pseudocoelom |
True coelom |
| Coelomic cavity |
Absent |
Pseudocoelomic cavity |
True coelomic cavity that is completely lined with mesoderm |
| Layers |
Diploblastic (ectoderm and endoderm) |
Triploblastic (ectoderm, mesoderm, and endoderm) |
Triploblastic (ectoderm, mesoderm and endoderm) |
| Body Wall |
Cellular mesenchyme |
Muscle cells under epidermis |
Muscular and connective tissue layers |
| Movement |
Ciliary gliding |
Muscular movement by pseudocoelomic fluid |
Muscular movement by coelomic fluid |
| Excretory System |
Protonephridia or flame cells |
Excretory tubules without specialized cells |
· Metanephridia
· Malpighian tubules |
| Examples |
· Flatworms e.g., Planarians |
· Roundworms e.g., Nematodes |
· Annelids
· Arthropods
· Chordates |
