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So far as the value of its form is concerned, it thus represents 
the very simplest morphological individual of the first order, 
a lump of plasma or a plastide. The variously interpreted 
definition of the organic cell is, according to the ordinary 
form of speech, no longer applicable to these very simple 
individualised morsels of plasma. In order, therefore, to 
make the cell theory, that indispensable foundation of our 
common tectology, applicable also to the Monera and the 
allied Protista, I have tried to define the relation of these 
morsels of plasma to true cells as sharply as possible in my 
tectology. According to my view, true cells, for the defi- 
nition of which I imagine necessary the separation of inner 
nucleus and outer plasma, have arisen from Monera by an 
inner differentiation. On the other hand, cell-like, hut non- 
nucleated, plastides — membranous cytodes — -have originated 
from Monera by an outer differentiation of plasma and en- 
closing membrane or shell. 
By this systematic division we obtain the following four 
essentially different elementary forms of Plastides, or of 
morphological individuals of the first order : 
Kinds of Plastides. 
I. Cytodae (or Cellinte), Cytodes, plasma-masses without a 
nucleus. 
1. Gyinnocytodse (or Cytoclee nudes), naked Cytodes. 
Naked plasma-masses without a nucleus, without a mem- 
brane or shell ; for example, the freely moving Monera, the 
non-nucleated plasmodia of the Myxomyceta, and of several 
other Protista, the amoeboid germs of the Gregarinac pro- 
ceeding from Pseudonavicclhe, &c. 
2. Lepocytodae (or Cytodce membranosce) , covered Cytodes. 
Encysted plasma-masses without nucleus, enclosed in an 
entire or incomplete membrane or shell; for example, the 
encapsuled resting condition of the Lepomonera, many 
Siphonese, and numerous other of the lower plants, the 
so-called “ non-nucleated cells” of many higher plants and 
of many animal tissues. 
II. Celluhn, (or Cyta) Cells, plasma-masses with nucleus. 
I. Gymnocyta (or Cellules nudes), naked cells. 
Naked plasma-masses with nucleus, without membrane or 
shell ; for example, the true Amoebae (Autamoebse), the naked 
zoospores of Algae, the eggs of Siphonophora and other ani- 
