Chapter 37 

 Order 2 Spirotricha. Butschli 



With free cilia only; exceptionally with small groups of cirrus-like pro- 

 jections in addition to cilia 

 Uniformly ciliated; in Peritromidae dorsal surface without cilia or 

 with a few cilia; in Licnophoridae cilia only on edge of attaching 

 disk; peristome usually extended; peristomal field mostly cili- 

 ated Suborder 1 Heterotricha 



Ciliation much reduced or none at all 



Rounded in cross-section; cilia usually much reduced; adoral zone 



encloses a non-ciliated peristomal field in spiral form 



Suborder 2 Oligotricha (p. 587) 



Compressed; carapaced; peristomal zone reduced to 8 membra- 



nellae which lie in a oval hollow 



Suborder 3 Ctenostomata (p. 600) 



Cirri only, on ventral side; dorsal side usually with rows of short 

 slightly movable bristles Suborder 4 Hypotricha (p. 603) 



Suborder 1 Heterotricha Stein 



Body ciliation complete and uniformly the same 



Peristome sunk in a funnel-like hollow at anterior end, thus mostly 



covered Family 1 Bursariidae (p. 574) 



Peristome lies almost completely free, leading to a short and narrow 

 oral funnel (absent in one family) 

 A narrow non-ciliated zone on right of adoral zone; usually an 

 undulating membrane or ciliary row to right of this non- 

 ciliated zone and anterior to cytostome; a small peristomal 

 field between the membrane and adoral zone 

 Adoral zone extends diagonally to posterior-right on ventral 

 surface; highly developed forms, with a long zone twisting 



spirally around body Family 2 Metopidae (p. 576) 



Adoral zone parallel to body axis on flat ventral surface, turns 

 somewhat to right in front of cytostome; oral funnel dis- 

 tinct; typically an undulating membrane or a double 



ciliated furrow in front of cytostome 



Family 3 Spirostomidae (p. 578) 



Without the non-ciliated zone; a large peristomal field with a half 

 or completely spiral adoral zone 

 Peristomal field not ciliated ; with a large undulating membrane 



on its right edge Family 4 Condylostomidae (p. 581) 



Peristomal field ciliated; without undulating membrane 



Peristomal field not drawn out in 2 wings; free-swimming or 



secretes gelatinous lorica 



Family 5 Stentoridae (p. 581) 



573 



