522 BIOLOGY OF THE PROTOZOA 



Family 2. Vorticellidae Ehr. 



1. Cup or test-dwelling forms 2 



Without test, with or without stalks, soli- 

 tary or colonial 5 



2. Upright; attachment posterior, with or 



without stalks 3 



Recumbent ; attachment lateral 4 



3. Cup delicate; peristome region cup-like 



Genus Ophrydiopsis Penard 

 Cup thick with or without stalk. . . .Genus Cothurnia Ehr. 



4. Peristome disc with neck; operculum-like 



Genus Lagenophrys Stein 

 Peristome disc without neck Genus Vaghricola Lamarck 



5. Forms with stalks 6 



Forms without stalks, free-swimming or 



attached 13 



6. Stalks contractile 7 



Stalks not contractile 9 



7. Colonial forms 8 



Solitary forms Genus Vortirelln Linn. 



8. Entire colony contracts; stalk threads con- 



nected Genus Zodtharnnium Ehr. 



Individual stalks, only, contract. . .Genus Carchesium Ehr. 



9. Colonial forms 10 



Solitary forms 12 



10. Great colonies of individuals embedded in 



jelly Genus Ophrydium Bory 



Feathery colonies, individuals not in jelly. 11 



11. Peristome region raised on short neck 



Genus Opercularia Stein 

 Peristome region without neck Genus Epistylis Ehr. 



12. Adoral zone with greatly developed mem- 



brane Genus Glossotella Biitschli 



Adoral zone inconspicuous Genus Rhdbdostyla Kent 



13. Free-swimming forms 14 



Attached by posterior end 16 



14. With digitiform protoplasmic processes 



Genus Hastatella Erlanger 

 Without digitiform protoplasmic processes 15 



15. With two caudal threads Genus Astylozoon Engelmann 



Posterior ciliated girdle permanent . .Genus Opisthonecta F. Frem. 



16. Posterior end with attaching disc. . Genus Scyphidia Lachm. 

 No attaching disc; organism rests on pos- 

 terior end or swims with posterior girdle 



Genus Gerda Clap, and Lachm. 



Sub-class IV. CHONOTRICHA Wallengren. 



1. Peristome region funnel-like Family Spirochonidae 



Peristome region drawn out as two lips 



Family Chilodochonidae 

 Family 1. Spirochonidae Grobben. 



1. Peristome spirally wound funnel. . .Genus Spirochona Stein 



(On gill plates of Gammarus) 

 Peristome not spirally wound 2 



2. Peristome margin with processes; 1 bud 



formed (On gill plates of Nebalia) .Genus Kentrochona Keuten 



Several buds formed Genus Kentrochonopsis Doflein 



(On gill plates of Nebalia) 



