| The position and composition of the cells suggests that they are homologous to the gliointerstitial cell system of molluscs, sipunculans, annelids echiurans. |
| In echiurans, sipunculans and in most polychaete annelids at least portions of the coelomic lining form the somatic and visceral musculature. |
| Morphology places sipunculans with annelids and molluscs, and their mitochondrial genes relate them to annelids. |
| The position and composition of these cells suggests that they are homologous to the gliointerstitial cell system of molluscs, sipunculans, annelids echiurans. |
| Siboglinids, echiurids, myzostomids, and sipunculans, are four taxa with enigmatic evolutionary origins. |
| Although mollusks, annelids, brachiopods, and sipunculans are closely related, the relationships between them are not well resolved. |
