Notes . 
159 
usually well formed ; the archegonia open in the usual manner, and 
the spermatozoids are capable of active movement when liberated. 
On other examples variously malformed sexual organs occur. The 
abnormal archegonia are seated upon small elevations composed of 
cells which contain chlorophyll; sometimes the neck is open, but 
other examples have the neck closed and branched. The central cell 
of the abnormal antheridium is arrested at a more or less early stage of 
development, while the cells of the wall and the base take on active 
growth. 
The sporangia are either isolated or associated together in groups, 
which bear a striking resemblance to sori. They are borne upon the 
process or close behind it upon the true middle lobe, and are rarely 
found upon prothalli which have not produced a cylindrical process. 
When this is the case, they are always isolated and situated on the 
edge of a thin continuation of the prothallus arising from the apical 
depression. 
Single sporangia occur frequently on the edge of the prothallus, 
which, as described above, crosses the base of the process. In 
a number of examples a single sporangium occupied a median 
position, and, from earlier stages observed, it is probable that it is to 
be traced back to the original growing-point of the prothallus. In 
other cases several sporangia were formed in this region. Isolated 
sporangia are also found on the process, but more frequently groups 
are met with. They occupy the upper or lateral faces of the process, 
and whenever sporangia in early stages of development are found, 
they are situated on its apex. It is probable that the groups of older 
sporangia had become displaced from this position by the further 
growth of the process. The groups were at a considerable distance 
from each other. 
The relative positions of sporangia and sexual organs is a point of 
some interest, and was readily determined. Archegonia were present 
close to the sporangia, and at the same level on the process. When 
the process, after producing sporangia, had continued its growth, 
archegonia and antheridia were present on the portion beyond the 
sporangia, as well as on the older part, and, in cases in which more 
than one group of sporangia had developed, the intervening region 
bore sexual organs. Rhizoids are also produced abundantly from the 
shaded side of the process, and, so far as external appearance is 
concerned, there is no reason to doubt the prothallial nature of the 
