2. Without cilia (in adult state) Subclass _Suctoria_
tentacles
3. a. Without a specialized fringe of Order _Holotrichida_
large cilia (ad. zone)
b. With general covering of cilia Order _Heterotrichida_
+ adoral zone
c. With cilia on ventral side Order _Hypotrichida_
+ adoral zone
d. With cilia in region of adoral Order _Peritrichida_
zone, and about mouth only