54 Fraser . — Contributions to the Cytology of 
30. Harper, R. A. (’00) : Sexual Reproduction in Pyronerna confluens and the Morphology of the 
Ascocarp. Ann. Bot., xiv, p. 321. 
31. (’05) : Sexual Reproduction and the Organization of the Nucleus in certain 
Mildews. Publ. Carnegie Institution, Washington, No. 37, p. 1. 
32. Maire, R. (’03) : Recherches cytologiques sur le Galactinia succosa. Comptes Rendus, cxxxvi, 
P- 769- 
33. — (’05) : Recherches cytologiques sur quelques Ascomycetes. Ann. Mycol., iii, p. 123. 
34. Mottier, D. M. (’07) : The Development of the Heterotype Chromosomes in Pollen Mother- 
cells. Ann. Bot., xxi, p. 309. 
35. Nemec, B. (’04) : Ueber die Einwirkung des Chloralhydrats auf die Kern- und Zellteilung. 
Jahrb. wiss. Bot., p. 645. 
36. Noll, T. (’05) : Die Pfropf-Bastarde von Bronvaux. Sitzungsber. Niederrhein. Ges. f. Natur- u. 
Heilkunde, Bonn, p. 34. 
37. Overton, J. B. (’06) : The Morphology of the Ascocarp and Spore formation in the many- 
spored Asci of Thecotheus Pelletieri. Bot. Gaz., xlii, p. 450. 
38. Schaffner, J. H. (’97) : The Life-History of Lilium Philadelphicum. Part III : The 
division of the Macrospore Nucleus. Bot. Gaz., xxiii, p. 430. 
39. Strasburger, E. (’80): Zellbildung und Zelltheilung. Jena. 
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EXPLANATION OF PLATES IV AND V. 
Illustrating Dr. Fraser's paper on Humaria rutilans. 
Fig. 1. Section through a very young ascocarp, lying against the wall of an older one. x 625. 
Fig. 2. Section through a rather older ascocarp. x 625. 
Fig. 3. Mitosis in hypothecium. x 1250. 
Fig. 4. Apogamous fusion in the hypothecium. x 1250. 
Fig. 5. The same, later stages. x 1250. 
Fig. 6. Nuclear migration in the hypothecium ; nuclei of two sizes are shown, x 1250. 
Fig. 7. Part of the subhymenial layer, showing nuclei in young ascogenous hyphae at a, and in 
a hypha just before crozier formation at b. (From the same ascocarp as Fig. 4.) x 1250. 
Fig. 8. Early prophase in the ascogenous hypha. x 1875. 
Fig. 9. Prophase in ascogenous hypha, showing sixteen chromosomes, x 2808. 
Fig. 10. Metaphase in ascogenous hypha. x 1875. 
Fig. 11. Telophase in ascogenous hypha. x 1875. 
Fig. 12. Proliferation of terminal cell of ascns. x 1250. 
Fig. 13. An ascus ( a ), the terminal cell connected with which has continued its growth and 
given rise to another ascus ( b ) ; from the terminal cell of which a third ascus (c) has arisen. 1250. 
Fig. 14. H, connexion between stalk and terminal cell. The nucleus of the latter has passed 
into the stalk-cell, from which a hypha is growing out. x 1250. 
Fig. 15. Nucleus migrating from the terminal into the stalk-cell, x 1250. 
FIRST DIVISION. 
Fig. 16. Two nuclei in the ascus, each showing the first contraction-figure of the heterotype 
prophase, x 1875. 
Fig. 17. Two nuclei in the ascus ; the beginning of the longitudinal fission can be distinguished 
in the spireme of each, x 1875. 
Fig. 18. Fusion in the ascus, the longitudinal fission is further advanced, x 1875* 
P'ig. 19. Definitive nucleus of ascus ; longitudinal fission complete, x 1875. 
Fig. 20. Synapsis. Longitudinal section of ascus. x 1875. 
