450 EXPLANATION OF THE FIGURES. 



Figs. 10 — 11. Alicularia scalaris. 



FIG. 



10. End of the stem being a half-ripe fruit, in a longitudinal section which 



has grazed the capsule and laid bare the outer surface of the fruit-stalk 

 and of the swelling at its lower end, x 30. 



11. Longitudinal section of a germ-plant, x 300. 



11*. A young leaf detached from the stem spread out, X 100. 



12. Jungermannia bicuspidata. — An archegonium just impregnated, and an un- 



impregnated one ; both laid open by a longitudinal section passing through 

 the perianthium, which already extends far above the archegonium, and has 

 the apices of its edges inclined towards one another. In the inner cavity 

 of the perianthium several moving spermatozoa were found ; the arrow 

 shows the direction of their motion. X 400. 



Figs. 13 — 20. Jungermannia divaricata. 



13. Longitudinal section of a rudimentary archegonium, x 600. 



14. Longitudinal section of a perianthium containing only two young arche- 



gonia, x 600. 



15. Archegonium ready for impregnation (or just impregnated ?), cut through 



longitudinally so that the knife passed through the central cell, x 600. 



16. The germinal vesicle detached from the central cell of a similar archegonium. 



The cell-membrane has been injured by the dissecting needle ; the 

 nucleus escaped out of the fissure, and lies near it, x 500. 



17. Longitudinal section of an impregnated archegonium which has grazed the 



two-celled fruit-rudiment. At the apex of the archegonium, between 

 the globular lumps of glassy transparent mucilage, thread-like bodies, 

 like spermatozoa are seen, x 600. 



18. A young, and 19, a somewhat older fruit-rudiment, the former seen from the 



outside, the latter in longitudinal section, x 100. 

 20. Longitudinal section of a more developed fruit, x 250. 



PLATE VEIL 



Figs. 1 — 20. Jungermannia bicuspidata. 



1. A very young perianth laid open by a longitudinal section, with three arche- 



gonia still closed at the apex, x 300. 



2. Longitudinal section of an archegonium ready for impregnation, x 300. 



3. Similar section of a somewhat more developed perianth. In the middle is 



an archegonium just impregnated ; near the latter are two unimpregnated 

 ones, with ruptured apex ; on the outside are two still undeveloped. 

 X 250. v 



4. Four-celled fruit-rudiment detached, x 300. 



5. Young fruit-rudiment. 5*. The same turned round 90°. 5 C . A similar 



fruit-rudiment detached, x 300. 



6. Longitudinal section of the lower part of a perianth enclosing two fruit- 



rudiments, x 250. 



