THE GENERAL STRUCTURE OF PLANTS 11, 
have a number of protoplasts arranged together over 
the inner surface of a common cell-wall. The separate 
protoplasts are often in such close contact with each other 
that, their separate outlines cannot be detected. They 
have the appearance of a mass of protoplasm lining the 
wall of a hollow, generally tubular, 
cavity, and having a large number 
of nuclei embedded in the mass. 
The presence of a number of nuclei 
indicates that there are really as 
many protoplasts, as we have seen 
a nucleus is an essential part of one 
of the latter. Moreover, a single 
protoplast contains only a single 
nucleus. 
The difference between a colony 
of this kind and one constructed 
like Chroococeus or Volvox is the 
absence of a cell-wall between the 
protoplasts. They are a stage 
higher than the Myxomycetes, as 
the whole colony is protected by an 
external membrane. 
Other ccenocytes exist in which, 
besides the limiting wall, certain 
transverse walls exist, dividing up 
the chamber into compartments. 
This condition is intermediate 
between the ccenocyte already de- F112 Euspyo or Orobus 
scribed and the simple colony or SUSPENSGR. ABE | aaa 
the multicellular plant. ture. (After Guignard.) 
In most cases the division of 
the cells goes on for a considerable time and may continue 
almost indefinitely, the number of the constituent proto- 
plasts becoming very great and the colony proportionately 
large. According to the direction of the divisions we 
get filaments (fig. 13), plates (fig. 14), or masses of cells, 
