旧きゅう口こう動どう物ぶつきゅうこうどうぶつMeanings1nounprotostomeZoological term for animals in which the mouth develops from the first embryonic opening (blastopore). Contrasts with 新口動物 (deuterostome).See also: 新口動物節せっ足そく動どう物ぶつや軟なん体たい動どう物ぶつは旧きゅう口