The orifice that connects the mouth to the exterior of the body.
Comment:
[homology-note] "(...) mouth development is very similar in protostomes and 'basal' deuterostomes, whereas the chordate mouth seems to develop at a new position. Recent data for echinoderms and hemichordates further suggest that this change in mouth position may result from change in the influence of a conserved ectodermal patterning system on mouth development. It has been suggested that the mouths of vertebrates and urochordates may constitute a 'new' mouth.[well established][VHOG]" xsd:string {date_retrieved="2012-09-17", external_class="VHOG:0000280", ontology="VHOG", source="DOI:10.1016/j.semcdb.2007.06.002 Christiaen L, Jaszczyszyn Y, Kerfant M, Kanob S, Thermes V, Joly JS, Evolutionary modification of mouth position in deuterostomes. Seminars in Cell and Developmental Biology (2007)", source="http://bgee.unil.ch/"}