EXPLANATION OF THE FIGURES. 457 



PLATE XVI. 



Pigs. 1 — 13. Fegatella conica. 



FIG. 



1. Section parallel to the surface of a shoot formed in autumn and destined 



for development in the following spring, x 30. 



2. One of the side shoots of this shoot, x 300. 



3. Longitudinal section perpendicular to the surface of a similar young shoot, 



X 300. 



4. Stornata, in process of development, X 300. 



5. Eudiment of a fruit-head (beginning of Pebruary), in longitudinal section, 



X 300. 



6. Young fruit-head from below, x 100. 



7. Fruit-head at that stage of development when the archegonia are ready for 



impregnation, X' 50. 



8. Young fruit-rudiment with the calyptra enclosing it, and the adjoining por- 



tions of the fruit-head, in longitudinal section, X 200. 



9. Five-celled fruit rudiment, detached, X 400. 



10. More developed fruit rudiment in longitudinal section, X 300. 



11, 12. 11 a very young, 12 a somewhat more developed leaf, x 300. 



13. Outline of a half-developed leaf, x 30. 



Figs. 14 — 20. Rebouillia hemispherica. 



14. Longitudinal section perpendicular to the surface through the very young 



rudiment of a shoot. X 300. 



15. Outer aspect of the same preparation, after it has been laid upon the sec- 



tional surface passing through the longitudinal axis of the shoot. The 

 rudiments of two leaves are seen. X 300. 



16. A young leaf, x 300. 



17. Longitudinal section perpendicular to the surface of a fertile shoot. On 



the right is a fruit-head ; the section has passed through two unimpreg- 

 nated archegonia and four scales. Stomate-formation is just com- 

 mencing in the covering cells of the air-cavities of the l'ruit-head. 

 Further back is a cushion of antheridia, cut through. The outlines of 

 the cells only are drawn, and the contents of the antheridia omitted. 

 X 300. 



18. An impregnated archegonium in longitudinal section. The mother-cell of 



the fruit-rudiment is still undivided. X 300. 



19. Longitudinal section of an impregnated archegonium, enclosing a more de- 



veloped fruit-rudiment. One only of the rows of cells of which the 

 young fruit-rudiment consists is seen ; the position of the nuclei of the 

 second is shown by a dotted circle, x 300. 



20. One of the sheathing prolongations of the fruit-head which enclose the 



fruit, seen from below. The curved neck of the impregnated arche- 

 gonium is also seen, x 30, 



