25 1 
Helvetia crispa, Fries . 
8. The spores are outlined by radiations from the centrosome, and 
when mature contain eight nuclei ; the divisions in the spore show two 
chromosomes. 
List of Papers. 
1. Claussen, P. : Zur Kenntniss der Kernverhaltnisse von Pyronema conflums. Ber. der deutsch. 
bot. Gesellsch., xxv, 1907, p. 586. 
2. Dangeard, P. : Sur le developpement du perithece chez les Ascomycetes. Le Botaniste, x, 
i 9°7. 
3. Digby, L. : On the Occurrence of Chromatin Bodies in Galtonia candicans. Ann. Bot., xxiii, 1909. 
4. Dittrich, G. : Zur Entwickelungsgeschichte der Helvellineen. Cohn’s Beitr. Biol. Pflanzen, 
1898, p. 17. 
5. Farmer, J. B., and Moore, J. E. S. : On the Meiotic Phase in Animals and Plants. Quart. 
Journ. Mic. Sci., 1905, No. 192, p. 489. 
6. Farmer, J. B., and Digby, L. : Apogamy and Apospory in Ferns. Ann. Bot., xxi, 1907. 
7. Fraser, H. C. I. : Contributions to the Cytology of Humaria rutilans. Ann. Bot., xxii, 
I9°S> P- 35- 
8. Fraser, H. C. I., and Welsford, E. J. : Further Contributions to the Cytology of the 
Ascomycetes. Ann. Bot., xxii, 1908, p. 465. 
9. Fraser, H. C. I., and Brooks, W. E. St. J. : Further Studies on the Cytology of the Ascus. 
Ann. Bot., xxiii, 1909, p. 537. 
10. Harper, R. A. : Sexual Reproduction and the Organization of the Nucleus in Certain Mildews. 
Publ. Carnegie Inst., Washington, No. 37, 1905. 
11. McCubbin, W. A. : Development of the Helvellineae. I. Helvetia elastica. Bot. Gaz., 1910. 
EXPLANATION OF PLATES XVIII AND XIX. 
Illustrating Miss D. Carruthers’ paper on the Cytology of Helvella crispa. 
All figures were drawn with a Zeiss apochromatic immersion lens, apert. 1*30 and compens. 
oc. 12 (magnification about 2000), with the exception of Fig. 41, for which compens. oc. 6 was used. 
PLATE XVIII. 
Fig. 1. Apogamous fusions in the hypothecium. 
Fig. 2. The same, later stage. 
Fig. 3. Mitosis in vegetative hypha. 
Fig. 4. Telophase of same. 
Fig. 5. Prophase in ascogenous hypha, showing four chromosomes. 
Fig. 6. Metaphase in fertile hypha, showing eight chromosomes. 
Fig. 7. Crozier with two nuclei in penultimate cell. 
Fig. 8. Fusion in ascus. 
Fig. 9. Connexion between stalk and terminal cell. 
Fig. 10. Nucleus migrating from terminal to stalk cell. 
Fig. 11. Formation of successive croziers. 
