The glandular canals present in some chaetognath species are coelomoducts: Phylogenetical implication
Résumé
The chaetognaths live in various marine habitats, mostly in plankton. Some species are provided with glandular canals, described herein; they are true coelomoducts. Their nature was already suspected but, curiously, this information was overlooked. Knowledge of this fact would have prevented numerous incorrect positioning of the phylum in the tree of life.