Geo that his tuber osus , Campbell. 
5°9 
EXPLANATION OF FIGURES IN PLATES 
XXIV AND XXV. 
Illustrating Professor Campbell’s paper on Geothallus tuberosus. 
PLATE XXIV. 
Except where otherwise stated, the drawings were made from microtome- 
sections of material fixed with chromic acid or absolute alcohol. 
Fig. 1. Nearly median section of the old thallus of Geothallus tuberosus , showing 
the tuber, t. x 20. 
Fig. 2. The hinder part of the tuber, x 300. 
Fig. 3. Forward part of the tuber surrounded by the overlapping leaves, and 
showing the apical cell, x ; x 300. 
Figs. 4, 5. A germinating tuber; a, from the side; b, from above; x 20. 
k, the young shoot. 
Fig. 6. Vertical section of the growing-point of a young shoot, x 300. x, the 
apical cell ; l, leaves. 
Fig. 7. Horizontal section of a similar apex, x 300. h, ventral hairs. 
Fig. 8. Young leaf, x 300. D, dorsal ; V, ventral margin. 
Fig. 9. Glandular hair from the ventral surface, x 300. 
Fig. 10. Male plant, with numerous antheridia, x 20. 
Figs. 11-16. Successive stages in the development of the antheridium, x 600. 
Fig. 15, cross-sections, the others longitudinal. In Fig. 15, a is a section through 
the stalk, b through the body of the antheridium. 
Fig. 17. An older antheridium, median longitudinal section, x 300. 
Fig. 18. Surface- view of the cells from the wall of the older antheridium, 
X 300. 
PLATE XXV. 
Fig. ] 9. Median longitudinal section of a nearly ripe living antheridium, showing 
the form of the envelope, x about 100. 
Fig. 20. Spermatozoids killed with osmic acid, x 1000. 
Fig. 21. Female plant, x 5. 
Fig. 22. End of one of the branches of the same, x 20. 
Fig. 23. Section of an older female plant, showing the archegonal envelopes 
(?)> x 5- 
Figs. 24-26. Young archegonia, median longitudinal sections, x 600. 
Figs. 27, 28. Two longitudinal sections of an older archegonium, x 300. The 
egg and ventral canal-cell only are shown in Fig. 28. 
Fig. 29. Venter of an archegonium, with two ventral canal-cells, V 1 , V 2 , 
x 300. 
Fig. 30. Longitudinal section of an open but unfertilized archegonium, x 300. 
Fig- 31. Venter of an open archegonium, showing the recently fertilized egg, 
x 300. 
