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Carruthers . — Cytology of Helvetia crispa , Fries. 
First Division. 
Fig. 12. Definitive nucleus of ascus, with chromatin of two nuclei undergoing first contraction 
separately. 
Fig. 13. Emission of chromatin body, spireme stage. 
Fig. 14. Same, later stage. 
Fig. 15. Same, showing thread passing through nuclear membrane. 
Fig. 16. Secondary buds from nucleolus. 
Fig. 17. Spireme with longitudinal fission. 
Fig. 18. Ditto. 
Fig. 19. The fission complete. 
Fig. 20. Second contraction. 
Fig. 21. Nucleus passing out of contraction, the fission once more visible in the loops. 
Fig. 22. Spireme broken up into chromosomes. 
Fig. 23. Immature chromosomes. 
Fig. 24. Chromosomes on spindle, centrosome and aster visible. 
Figs. 25, 26. Chromosomes on spindle. 
Fig. 27. Metaphase with eight daughter chromosomes. 
Fig. 28. Chromosomes passing to poles. 
Fig. 29. Telophase. 
Fig. 30. Reconstitution of daughter nuclei. 
PLATE XIX. 
Second Division. 
Fig. 31. Chromosomes breaking apart. 
Fig. 32. Spindle with eight daughter chromosomes. 
Third Division. 
Fig* 33 * Prophase of third division. 
Fig. 34. Metaphase, two chromosomes passing to each pole. 
Fig. 35* Telophase. 
Fig. 36. Late telophase with astral rays. 
Fig. 37. Formation of nuclear beaks. 
Fig. 38. Spore formation. 
Fig. 39. Mitosis in spore. 
Fig. 40. Proliferation of terminal cell of crozier. 
Fig. 41. Secondary nuclei formed by division without spore formation. 
Fig. 42. Two nuclei in ascus, which have failed to fuse. 
