`` Xenoturbella '' has a very simple body plan : it has no brain , no through gut , no excretory system , no organized gonads ( but does have gametes ; eggs and embryos occur in follicles [ Israelsson and Budd ] ) , or any other defined organs except for a statocyst containing flagellated cells ; it has cilia and a diffuse nervous system .
`` Xenoturbella '' has a very simple body plan : it has no brain , no through gut , no excretory system , no organized gonads ( but does have gametes ) , or any other organs except for a statocyst containing flagellated cells . It has cilia and a diffuse nervous system .