204 BOTANICAL GAZETTE [SEPTEMBER 
Fic. 11. Longitudinal section of a young antheridium, showing the seven 
primary tiers of cells and the separation of the wall cells from the sperma- 
togenous cells. x 
Fic. 12. stiins section of a slightly older antheridium. X 350, 
1G. 13. Similar section of an antheridium and an antheridial cavity of the 
male receptacle. X 350. 
1G. 14. Longitudinal section of an older antheridium. X 160. 
Fic. 15. Transverse section of a young antheridium and soe cells 
showing a primary longitudinal wall of the antheridium. x 650. 
Fic. 16. Similar section of an antheridium showing quadrant walls. X 650. 
Fic. 17. Similar section of an antheridium in which spermatogenous cells 
and the ons wall have been differentiated. x 650. 
1G. 18. Transverse section of an older re showing the mode of 
division of fe four primary spermatogenous cells. X 350. 
Fics. 19-20. Similar sections of still older antheridia, showing multiplica- 
tion of spermatogenous cells. X 160. 
1G. 21. Portion of longitudinal section of nearly mature antheridium, 
showing the wall and the three-cornered spermatozoid mother-cells. X 350. 
Fic. 22. View of the upper surface of part of a female plant, showing an 
involucre containing two young sporogonia, one containing a nearly full-grown 
sporogonium, and one from which a capsule has as already been extended. X 15. 
Frcs. 23-24. Optical longitudinal sections of tuberculate rhizoids. x 650. 
Fic. 25. Portion of the edge of the thallus with thick-walled marginal rhizoids. 
160. 
Fic. 26. Longitudinal section through the growing point of a female plant, 
showing the beginning of the pit in which the archegonia arise. X 75- 
PLATE XVII. 
Fic. 27. Lower portion of the same section, showing the slime-secreting 
hairs and the cells which are to form archegonia. X 350. 
Fic. 28. Longitudinal section of an older archegonial pit, showing the half 
grown involucre and two mature archegonia. X 38. 
Fic. 29. Similar section of a full-grown involucre, containing an archegonium 
with a _ embryo. X8. 
Fic. 30. Transverse section of fertile branch of female thallus passing through 
an hits containing a nearly mature sporogonium. 8. 8 
IG. 31. Longitudinal section of similar involucre and sporogonium. ” 
Fic. 32. Longitudinal section of a young archegonium. eee 
Fic. 33. Longitudinal section of a mature archegonium. eat 
Fig. 34. Transverse section of neck of archegonium, ene eight 
cells. X 160 
Fic. ae: Similar section of ahaa at juncture of 
showing a normal six-celled neck. 300. : earlier 
Fics. 36-37. Longitudinal AS of young embryos, showing sc 
walls in the latter. x 350. 
neck and vente 
