1918] CRIBBS~MARCHANTIA 93 
ing. ‘The sporogenous cells are in the compact spore stage follow- 
ing the development of tetrads. 
The columella, which at this stage is clearly defined, extends 
from the base of the capsule through more than three-fourths of 
its length. It is composed largely of elaters which diverge slightly 
at the free end. Intermingled with the elaters occur tissues 
developed from sporogenous cells which have elongated and divided 
transversely a number of times, but failed to reach the spore 
mother cell stage; thus remaining as elongated sterile chains of 
cells which will not develop into elaters, but may, as in fig. 1, com- - 
pletely disintegrate during the later history of the capsule, or in 
this more compact columella there may be but a partial dis- 
organization. This type of structure, judging from its position 
and development, is suggestive of the elaterophore of Pellia. It 
has a less advanced state of organization, however, since there is 
no apparent tendency either to diminish the number of diffusely 
scattered elaters or to assemble them at the apex of the column. 
Another phase in the development of sterile tissue within the 
capsule is met with in the group of cells which occur at the apex. 
The development of sterile cells at this point at once recalls the 
condition existing in Ameura. Krenttz-GERLoFF refers to the 
development of two layers of sterile cells here. Examination of a 
large number of sporophytes, however, will show that there is con- 
siderable variation in the amount of this tissue, and also that it 
may be formed in different ways. 
Fig. 4 represents a young sporophyte when the greater density 
of the protoplasm in the distal half is just becoming manifest. 
There has been no separation of sterile tissue at the apex up to this 
stage. In this instance two eggs have been developed in the venter, 
only one of which is seen to be developing an embryo. It would 
seem, from the fact that all the other eggs developed on this recep- 
tacle were fertilized and forming sporophytes, that the failure of 
this one to do so may be attributed to a potential sterilization 
which follows the initial development of the egg first fertilized, a 
response comparable perhaps to that of Pellia or Pallavicinia, 
where but one sporophyte regularly develops from a group of closely 
assembled archegonia. 
