18.The proter's oral primordium appears (under the pellical, too) anterior to the parent AZM2, from which membranells 7―11 of AZM1, the whole AZM2, PM and one of the frontal cirri will be originated;
(2)前仔虫口原基出现在老仔虫AZM2之前方深处,其随后发育成前仔虫
AZM2、口侧膜及AZM1
一部分,并更新老结构AZM1中
第7―11片小膜。