THE INFUSORIA 



207 



Family 3. Chlamydodontidae. The general form is oval or kidney-shaped. The 

 mouth is almost always in the posterior region. The pharynx is supported by a 

 rod-apparatus or a smooth, firm tube. 



Subfamily 1. Nassulincz. Ciliation is complete. Genera: Nassula Ehr. ('33). 



Subfamily 2. Chilodontina. The body is generally flattened, and the cilia are 

 stronger on the dorsal side, or are confined to that region. Genera : Orthodon 

 Gruber ('84); Chilodon Ehr. ('33); Chlamydodon Ehr. ('35); Opisthodo7i 

 Stein ('59) ; Phascolodon Stein ('57) ; Scaphidiodon Stein ('57). 



Subfamily 3. Erviliince. The cilia are confined to the ventral surface or to a por- 

 tion of it. The posterior end invariably possesses a movable style arising from 

 the posterior ventral surface. Genera: sEgyria Clap. & Lach. ('58); 

 Onychodactylus Entz. ('84) ; Trochilia Duj. ('41 ) ; Dysteria Huxley ('57). 



Suborder 2. TRICHOSTOMINA. In addition to the general coating of cilia there is 

 an undulating membrane or membranes at the edge of the mouth or in the 

 pharynx. The mouth is always open. 



Family 1. Chiliferidae. The mouth is in the anterior half of the body or close to 

 the middle The pharynx when present is short. The so-called "peristome 

 area" leading to the mouth is absent or only slightly developed. Genera: 

 Leucophrys Ehr. ('30) ; Glaucoma Ehr. ('30) ; Dallasia Stokes ('86) ; Fron- 

 totiia Ehr. ('38); Uphryoglena Ehr. ('31); Colpidium Stein ('60) ; Chasmato- 

 stoma Engelmann ('62) ; Uronema Duj. ('41) ; Urozona Schewiakoff (Butschli) 

 ('68); Loxocephalus Kent ('81) ; Colpoda Miiller (1773). 



Family 2. Urccen'iridse. The mouth, with a long, tubular pharynx, is in the centre 

 of the ventral side. The cilia are confined to two broad zones around the body 

 at each end. Genera: Urocentrnm Nitsch ('27). 



Family 3. MicrothoracidEe. Small asymmetrical forms, with the mouth invariably 

 in the hinder portion. The cilia are always more or less dispersed, sometimes 

 limited to the oral region. There may be one or two undulating membranes. 

 Genera: Cinetoclulum Perty ('49); Microthorax Engelmann ('62); Ptychosto- 

 miim Stein ('60) ; Aucistrian Maupas ('83) ; Drepanomonas Fresenius ('58). 



Family 4. Paramoecidse. The mouth is sometimes in the anterior, sometimes in 

 the posterior, half of the body, and is accompanied by a large, triangular "peri- 

 stome area" running from the left anterior edge of the body to the mouth. 

 Genera: Paramecium Stein ('60). 



Family 5. Pleuronemidae . The mouth is at the end of a long peristome which 

 runs along the ventral side ; the body is dorso-ventrally or laterally compressed. 

 The entire left edge of the peristome is provided with an undulating membrane 

 which occasionally runs around the posterior end of the peristome to form a 

 pocket leading to the mouth. The right edge of the peristome is pro- 

 vided with a less developed membrane. There may or may not be a well- 

 developed pharynx. Genera: Lembadion Perty ('49) ; Pleuronema Duj. C41); 

 Cydidium Ehr. ('38), a sub-genus of the preceding; Calyplotricha Phillips 

 ('82); Lembus Cohn ('65). 



Family 6. Isotrichidae. The body is more or less plastic, but not contractile. The 

 cuticle is thick and provided with evenly distributed cilia. The mouth is 

 posterior and accompanied by a distinct pharynx. They are parasites in the 

 digestive tract of ruminants. Genera : Isotricha Stein ('59) ; Dasytricha Schu- 

 berg ('88). 



Family 7. Opalinidse. The form is oval, and the body may be short or drawn out 

 to resemble a worm. They are characterized mainly by the absence 1 of mouth 

 and pharynx. Genera: Anoplophrya Stein ('60); Hoplitophrya Stein ('60); 

 Discophrya Stein ('60) ; Opalinopsis Fcettinger ('81) ; Opalina Purkinje and 

 Valentin ('35) ; Monodontophrya Vejdowsky ('92). 



