SPECIAL MORPHOLOGY AXD TAXONOMY OF IXFUSORIA 405 



12. Ventral ciliated surface very narrow Genus Dysteria 

 Ventral ciliated surface broad 13 



13. Dorsal surface markedly convex. . . .Genus Phascolodon 

 Dorsal surface slightly arched 14 



14. Ventral surface like Chilodon, wdth poste- 



rior spine Genus Dysteropsis 



Ventral surface uniformly ciliated, no spine 15 



15. Cilia arranged in bands 16 



Cilia in uniform rows 17 



16. With dorsal keel or ridge Genus Scaphidiodon 



No dorsal keel or ridge Genus Trochilia 



17. With oblique fringe of longer cilia to mouth 



Genus Onychodadylus 



Without such fringe Genus J^gyria 



Family 4. Trachelinidse. 



1. Proboscis single, more or less developed; 



■R-ith mouth 2 



Proboscis double or triple; no definite 

 mouth 7 



2. Circular mouth at base of proboscis, dorsal 



Genus Trachelius 

 Mouth on ventral concave surface 3 



3. Mouth slit-like .4 



Mouth a circular pore at base of proboscis 



(Fig. 6, p. 28) Genus Dileptus 



4. IVIouth from tip to base of well-defined 



proboscis (Fig. 30, p. 70) Genus Lionotus 



Proboscis rudimentary 5 



5. jVIouth arcuate, just below beak-like pro- 



boscis (Fig. 167) Genus Loxodes 



Mouth straight, more or less oblique 6 



6. Body flask-shape or slightlj' compressed 



Genus Amphileptus 

 Body flat (Fig. 167) Genus Loxophyllum 



7. Two anterior, lateral, hollow, arms . Genus Arachnidiopsis 

 Three jDroboscides, each Dileptus-\ike 



Genus Teutophrys 



Sub-order 3. Trichostomina, Ehrexberg, Steix. 



1. Cilia not in zones 2 



Cilia in two broad zones; with caudal tuft 



Family 1. Urocentrid.e 



2. Body with small circular or ellipsoidal 



peristome 3 



Body with large prominent peristome 4 



3. Mouth in anterior half of body, .Family 2. Chiliferid.e 

 Mouth in posterior half of body. Family 3. Microthoracid.e 



4. One or more huge undulating membranes 



in peristome Family 4. Pleuronemid.e 



Undulating membrane in gullet . Family 5. Paramecid.e 

 Parasitic forms in stomach of horse and 



ruminants Family 6. Isotrichid.e 



Family 1. Urocentridse, Clap, and Lach. 



One genus witli characters of the family (Fig. 



168) Genus Urocentrum 



