op 



ts 



.-Periatomiale 

 ' Apertura 



Periatoniale 

 . -Ascopore 



-Frontal 



Peristomial ovicell-- 



Peristome 



P.eristomice 



Apertura 



Asoopore 



. Base of se^nent 



Articulation of segment 



;,KI Fi<i. 150. Aiuitoiniciil structure of the family TubucelUinidae BusU, 1884. 



