part_of part of part of only in taxon in taxon connects develops from immediate transformation of Acoelomorpha Siboglinidae Eumetazoa tube mouth digestive system digestive tract we following Kardong in naming the entire tube from mouth to anus the alimentary canal. Kardong calls the portion of this tract that excludes buccal cavity and pharynx the 'alimentary canal', consider adding an extra class for this presumptive gut