H. Test angularly oblong, bottle-shaped T. euchlora 



11. Test oblong-cylindric, lateral margins parallel T. dubia 



12. Test beset with long or short spines 13 



12. Test without spines; either smooth or with granules or warts 16 



13. Rim of collar beset with stout spines T. armata 



13. Rim of aperture smooth 14 



14. Test oval, with long, stout spines T. horrida 



14. Test broadly oval to subspherical, with short spines or sharp warts . . 15 



15. Test subspherical, beset with sharp warts or very short 



spines T. hispida 



15. Test oval, beset with stout spines T. charkowiensis 



16. Test smooth 17 



16. Test granular, rugose, or spiny 20 



17. Test with mammillate collar; spherical T. mammillosa 



17. Test without a mammillate collar; cylindric or oval 18 



18. Test cylindrical T. cylindrica 



18. Test oval or spherical 19 



19. Test spherical with an inward projecting flagellar tube T. various 



19. Test broadly ellipsoid or oval, with short curved collar T. Playfairii 



20. Test oval, (19)— 23— 25m in diameter, 31— 33jli 



long, uniformly granular T. crebea 



20. Test ellipsoid to ovoid, smaller, (5)— 19/x, in diameter 21 



21. Test oval, 5— 11— 17m in diameter, 17m long T. pulchella 



21. Test ellipsoid, 19m in diameter, 21m long T. granulosa 



22. Test triangular, flagellum aperture occupying the entire 



apex T. triangularis 



22. Test some other shape; aperture narrower 23 



23. Test spherical or subspherical 24 



23. Test elongate, ovoid or cylindrical 28 



24. Test smooth 25 



24. Test warty or spiny 27 



25. Test broadly oval, 16— 18m in diameter T. intermedia 



25. Test spherical 26 



26. Test spherical to subspherical; wall thick, 



coarsely punctate T. rotunda 



26. Test perfectly spherical, wall thin, smooth or finely 



punctate T. volvocina 



27. Test nearly spherical, with a few teeth in the vicinity 



of the flagellum aperature T. acanthostoma 



27. Test broadly oval, evenly beset with short, sharp spines T. robusta 



28. Test cylindrical 29 



28. Test elliptic, oval or subcylindric-oval 30 



29. Test with margins nearly parallel, 12— 16m in diameter, 



26— 29m long T. lacustris 



29. Test subcylindric, the margins slightly convex, test 



15.6 X 31m T. erecta 



30. Test elliptic 31 



30. Test oval or subcylindric-oval 33 



31. Test broadly elliptic, 23— 34m in diameter; 



wall granular T. Kelloggii 



31. Test smaller; wall smooth 32 



32. Test narrowly elliptic, twice as long as broad T. pulcherrima 



32. Test broadly elliptic to oval, 1 1/3 as long as broad T. Dybowskii 



409] 



