19 
of Marattia Douglasii , Baker. 
Owing to the very small number of the eusporangiate 
Filicineae now existing,, we can never hope to trace out an un- 
broken line of descent, but when the numerous fossil remains 
have been as carefully studied as the living ones, much 
additional information bearing on the subject may be reason- 
ably expected. 
EXPLANATION OF FIGURES IN PLATES 
I AND II. 
Illustrating Professor Campbell’s paper on Marattia. 
PLATE I. 
Fig. I. Horizontal section of the apex of a small prothallium with two initials, 
x, x . x 300. 
Fig. 2. Vertical section of the apical region of a prothallium ; ar, archegonium ; 
x, one of the apical cells, x 50. 
Fig. 3. Apical region of a similar section. X300. x, apical cell; d, dorsal 
segment ; v, ventral segment. 
Fig. 4. An old prothallium with adventitious buds b. x 2. 
Figs. 5-7. Surface views of antheridia in different stages. In Fig. 7 the dotted 
lines indicate the lateral cells ; 0, opercular cell, x 300. 
Figs. 8-10. Vertical sections of young antheridia. X300. 
Figs. 11, 12. Young spermatozoids. X1200. 
Figs. 13-16. Development of the archegonium. 13, 14 x6oo: 15, 16 X300, 
b, basal cell ; 0 , egg ; c , neck-canal-cell ; v , ventral canal-cell ; n, neck ; m, peri- 
pheral cells. 
Fig. 17. Cross-section of the base of the archegonium. x 300. 
Fig. 18. Lower part of archegonium with ripe egg. X650. 
Fig. 19. Recently fertilized egg showing the spermatozoid in contact with the 
egg-nucleus, x 650. 
Fig. 20. A later stage, x 650. 
Fig. 21. Fertilized egg showing almost completed fusion of the sexual nuclei. 
x6oo. 
Fig. 22. Vertical section of young embryo, x 300. b b, basal wall. 
Fig. 23. Diagram of the same embryo, b b , basal wall ; II II, transverse wall. 
Fig. 24. Vertical section of an older embryo. X300. The arrow indicates 
the position of the archegonium. 
C 2 
