Chapter 42 

 Order 4 Peritricha Stein 



THE peritrichous ciliates possess a much enlarged disk-like 

 anterior region which is conspicuously ciliated. The adoral 

 zone is counter-clockwise to the cytostome viewed from the 

 anterior end. The body ciliation is more or less limited. The 

 stalked forms produce free-swimming individuals, telotrochs. 

 Asexual reproduction is by binary fission; and conjugation occurs 

 commonly. The majority are free-living, often attached to various 

 aquatic animals and plants, although a few are parasitic. 



Attached to submerged objects; usually no body cilia, though telotroch 

 possesses a posterior ring of cilia Suborder 1 Sessilia 



Free-swimming; but with highly developed attaching organellae on 



aboral end which are ciliated permanently 



Suborder 2 Mobilia (p. 625) 



Suborder 1 Sessilia Kahl 



Without lorica, although some with a gelatinous or mucilaginous en- 

 velope Tribe 1 Aloricata 



With definite pseudochitinous lorica Tribe 2 Loricata (p. 623) 



Tribe 1 Aloricata Kahl 



Posterior end with 1-2 short spines; swimming with peristome-bearing 



end forward Family 1 Astylozoonidae 



Posterior end, directly or indirectly through stalk, attached to sub- 

 merged objects 

 Anterior region a long cylindrical, highly contractile neck; con- 

 tractile vacuole posterior, connected with vestibule by a long 

 canal; reservoir of contractile vacuole distinct; with or without 



a thin stalk Family 2 Ophrydiidae (p. 618) 



Anterior portion not drawn out into a neck 



Without stalk Family 3 Scyphidiidae (p. 618) 



With stalk 



Stalk non-contractile Family 4 Epistylidae (p. 619) 



Stalk contractile Family 5 Vorticellidae (p. 621) 



Family 1 Astylozoonidae Kahl 



Genus Astylozoon Engelmann (Geleiella Stiller). Free-swim- 

 ming; pyriform or conical; aboral end attenuated, with 1-2 



616 



