THE GENERAL STRUCTURE OF PLANTS 11 
important seaweeds and by a large number of fungi, as well 
as by particular parts of some of the flowering plants, we 
have a number of protoplasts arranged together over the 
inner surface of a common cell-wall. The separate proto- 
plasts are often in such close contact 
with each other that their several 
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 pre- 
sence of a number of nuclei indicates 
that there are really as many pro- 
toplasts, as we have seen a nucleus 
is an essential part of one of the 
latter. Moreover, a single proto- 
plast 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 nicer pes exist in which, Fig. 12.—Empryo oF Orobus at 
besides the limiting wall, certain cms Basz or a Lone Sus- 
transverse wally exist, dividing up #808. Tan Larrer snows 
s A Ca@nooytio SrRuctuRE. 
the chamber into compartments. (After Guignard.) 
This condition ig intermediate 
between the ccenocyte already described and the simple 
colony or the multicellular plant. 
In most cages the division of the cells goes on for a con- 
siderable time and may continue almost indefinitely, the 
number of the constituent protoplasts becoming very great 
and the colony proportionately large. According to the 
