66 BOTANICAL GAZETTE [JANUARY 
function while the antheridial group is developing, but later con- 
tinues the: growth of the thallus. In Dumortiera the antheridial 
receptacle is lifted up on a short stalk and represents a definite 
branch system which terminates apical growth of the thallus. 
In Marchantia the situation is similar, but the stalk is long. 
Fics. 3-5.—Fig. 3, pore on male receptacle through which sperms escape, 479°; 
hamb 1 in femal tacle, X 250; fig. 5, cell from ventral region 
. 4, air I 
showing intracellular fungus, < 470. 
The development of the antheridia of Reboulia is similar to 
that of the other Marchantiales which have been investigated. 
The superficial papillate initial is soon overgrown by the adjacent 
cells of the thallus, so that the antheridium comes to lie in a pit; 
the development of the antheridial pit is therefore very different 
from that of the air chambers. The first division of the initial is 
transverse and separates the imbedded portion of the stalk from 
the rest of the antheridium (fig. 7). Additional transverse walls 
