June, 1922] 
DUPLER — ■ REBOULIA HEMISPHAERICA 
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gonia^may occur on the male receptacle (figs. 17, 18) or antheridia on a 
female receptacle (figs. 20-22). In the former case some of the antheridia 
were only partly enclosed by the chamber (fig. 19) or were raised above the 
surface of the disc by the elongated stalk (fig. 18). The young antheridia 
Figs. 16-22. Figure 16, median longitudinal section of a half-grown antheridium 
within the antheridial chamber. X 205. Figures 17 and 18, "male receptacles" with 
archegonia. X 82. Figure 19, young antheridium of figure 17. X 370. Figure 20, 
"female receptacle" with young antheridium (shown in black). X 82. Figures 21 and 
22, young antheridia found in receptacle shown in figure 20. Figure 22 is the detail of the 
antheridium shown in figure 20. The section was cut obliquely across the antheridium. 
X 650. 
found on the female receptacle were deeply imbedded within the tissue. It 
is probable that bisexual receptacles will be found in still other forms of the 
Marchantiaceae, their significance lying in the occasional reversion to a 
primitive feature, and, as Cavers (8) suggests, they ''demonstrate the ho- 
