34. Body Advances Sponges Cnidaria Symmetry Absent Radial Digestive System Absent Gastrovascular Cavity Support Endoskeleton Hydrostatic Skeleton Nervous System Absent Nerve Net Tissues Absent Present Germ Layers Absent Two
48. Annelids move forward by using peristaltic contractions of the circular muscle and turn by contracting the longitudinal muscles. Roundworms move using a thick layer of obliquely arranged muscle fibers just under epidermis, they lack circular muscles so motion is always undulatory. Annelid Roundworm Body cavity Coelom Pseudocoelom Segmentation Present Absent Circulatory System Closed Absent Excretory System Metanephridia Excretory gland cells Nervous System Brain, ventral nerve cord Brain, nerve cord