EXPLANATION OF THE FIGURES. 453 



Eigs. 8 14, 27 42. Frullania dilatata. 



FIG. 



8", *, c . Three successive stages of development of superior leaves. In, 

 fig. 8 C the under lobe of the leaf is shown as a single row of cells. 

 8" and 8 6 are x 300, 8 C is X 150. 



0. Leaf bud seen from above, X 200. 



10. Leaf bud seen from the upper side, X 200. 



11. A young inferior leaf, x 300. 



12. Two lobes of a youug superior leaf spread out, X 200. 



13. 14. Upper lobes of older superior leaves, x 200. 



27. Ripe spore just set free, X 300. 



28, 29. Spores at the beginning of germination, having become bicellular, 



X 300. 



30 36. Outlines of the cells of germinating spores ; in figs. 30 33 the outer 

 spore-membrane is shown ; 36* is the germ-plant shown in fig. 36 turned 

 round 90. 



37, 38. Germ-plants more developed seen from the outside. 



39. A very young, 40 a more developed, 41 a half-ripe, 42 a ripe ruptured 

 antheridium ; near the latter are some escaped mother-cells of sperma- 

 tozoa, from some of which the spermatoza have already escaped, x 400. 



PLATE XII. 



FRULLANIA DILATATA. 



1. Two young archegonia surrounded by the rudiment of the perianth, x 400. 



2. Longitudinal section of a perianth seen from the outside, X 400. 



3. Longitudinal section of an inflorescence containing two half developed and 



one impregnated archegonium, X 400. 



4. Longitudinal section of the lower part of an impregnated archegonium, 



with a seven-celled fruit-rudiment, X 400. 



5. Longitudinal section of a more developed fruit-rudiment, with the arche- 



gonium becoming transformed into the calyptra, x 400. 



6. 7. Young fruit-rudiments, detached. 6 and 6 4 , 7 and 7b, are the same pre- 



parations, 6 and 7 being the figures obtained by adjusting the microscope 

 to the longitudinal axis, and 6 4 and 7 b by adjusting it to the outer sur- 

 face, X 400. 



8. Longitudinal section of a more developed fruit, at the time of the differ- 



entiation of the capsule-wall and contents, x 300. 



9. Longitudinal section of a half-ripe fruit, x 300. 



10. Spore-mother-cell with four protrusions (one turned away from the ob- 

 server) of the membrane, taken from a similarly developed capsule, 

 x 300. 



