DESCRIPTIONS OF THE PLATES. 



Note. — The following figures have been reproduced, by photo-lithography and the heliotype process, 

 from ink drawings made with a camera lucida, and have been slightly reduced from the origi- 

 nals. The letters and numbers following the descriptions of the figures indicate the combina- 

 tions of Zeiss objectives and eye-pieces used in each case. 



DESCRIPTION OF PLATE L 



Stigmatomyces Baeri Peyritsch. 



Pigs. 1 to 15. Successive stages from the spore to the formation of the mature female organ. 

 See p. 218. All J 2. 



Fig. 16. Terminal portion of young perithecium, showing nucleated trichogyne and trichophoric 

 cell before fertilization. J 4. 



Pig. 17. Young perithecium in which fertilization has just been accomplished. J 2. 



Figs. 18, 19. Young perithecium after fertilization. The first divisions of the carpogenic cell 

 have taken place. J 2. 



Fig. 20. A more advanced condition in which the ascogonium has divided into four ascogenic 

 cells (ac) and a secondary inferior supporting cell (ist). J 2. 



Fig. 21. A somewhat more advanced condition of the same. J 2. 



Fig. 22. A more advanced condition in which the asci have begun to bud from the ascogenic 

 cells. A slightly oblique lateral view. J 2. 



Fig. 23. A still more advanced condition showing the further development of the perithecial 

 cells and their relations to the ascogenic and supporting cells. An optical section seen antero- 

 posterior^. J 2. 



Fig. 24. Terminal portion of a mature perithecium just before the first spore discharge. The 

 upper and lower series of canal cells (tc and c) are still intact, the latter beginning to be pressed apart 

 by the spore mass (sm). The inferior canal-cells (nc) have become somewhat modified through the 

 thickening of their walls, and form a diaphragm between the general cavity of the perithecium and 

 that of the neck. J 2. 



Fig. 25. A single four-spored ascus isolated. J 2. 



Fig. 26. Terminal portion of an appendage showing two antheridial cells with antherozoids both 

 mature and in process of formation. J 12. 



Peyritsehiella geminata Thaxter. 



Fig. 27. Young perithecium, in which the trichogyne has not been fertilized. T ^ 4. 



Fig. 28. Young perithecium after fertilization in which the carpogenic cell has divided into the 

 inferior and superior supporting cells while the ascogonium has divided into a single ascogenic cell 

 (ac) and a secondary inferior supporting cell (ist) . ^ 4. 



