Introduction to Animal Morphology. 7 1 



5. Ophryoscolecids — naked forms (found in the paunch 

 of Ruminants) with an anterior crown of a few cilia. 



Sub-order 2. Holotricha — uniformly ciliated, including 

 seven families. 6. Cyclidinidas — aproctous, body flat or oval, 

 sometimes bristly, Cyclidium. 7. Enchelidse — mouth and 

 anus at opposite poles ; pharynx with no teeth ; body naked, 

 oval (Enchelys), or with a long, narrow neck, and a laterally 

 lipped mouth (Lacrymaria). Leucophrys is parasitic, with a 

 wide neck and an ad-oral ciliary spiral. 8. Chilodontidse 

 have an oval, striated surface with rows of cilia, mouth tubular, 

 anterior (Prorodon), or beneath, with lips and tooth-like pro- 

 cesses. The teeth may be numerous, as a wheel-like circlet 

 of hooks (Nassula), or with a lip-like anterior process 

 (Chilodon). In these, living embryos arise by a process of 

 encystation. Wagneria, whose mouth apparatus resembles 

 that of Prorodon, has two distal ciliated zones like 

 Trichodina. 9. Colepidae — loricated, with mouth and anus 

 at opposite poles ; shell striated, perforated, toothed in front 

 and behind. 10. Tracheliidae — ciliated, shell-less, longitudi- 

 nally striated, oval or irregular, with an antero-inferior mouth, 

 no teeth, and a narrow anterior proboscis, with sometimes 

 eyelid-like valves to the mouth (Glaucoma). Trachelius is 

 mentioned before (p. 67, Fig. 7). 11. Ophryocercidae — 

 mouth anterior, anus ventral ; the front end is sometimes 

 bifid (Trachelocerca biceps, Fig. 8, B). 12. Colpodidse — shell- 

 less, mouth and anus ventral, sometimes with a tongue-like 

 tuft of oral cilia (Colpoda, common in hay infusions), or 

 with eye-specks (Ophryoglena). Amphileptus has no tongue- 

 like process, and is narrowed fore and aft into a proboscis 

 and tail. Uroleptus has only a tail. Paramaecium (Fig. 6), 

 very common ; has a compressed slipper-shaped body, a 

 lateral mouth, and stellate contractile vesicles. 



Sub-ord-er 3. Heterotricha — possessing a second, longer 

 set of cilia near the mouth, and fine cilia over the body. 

 This includes two families. Bursaridae, with the mouth at 

 the bottom of a deep slit, not anterior, and guarded by long 

 cilia. The anus is posterior ; the peristome is not spiral. 

 Bursaria is parasitic (in Man, Swine, Frogs). Spirostomum, 

 the largest Infusorium, is flattened and elongate, with a 



