At the anterior end of the preoral lobe is a nervous thickening of the ectoderm called 226 the apical plate .
Prostomium: The region in front of the mouth; the preoral part of the head.
The cilia of the preoral and postoral bands are not clearly differentiated at this stage.
To the right of this adoral zone is a single line of preoral cilia.
preoral pre·o·ral (prē-ôr'əl)
Situated or located in front of the mouth.