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organic “ kingdom.” Thereby we obtain the advantage of 
being able to distinguish both true animals and true plants 
by a clear and sharp definition, and, on the other hand, a 
special proportion of attention is attracted to the very low 
organisms hitherto so much neglected, and yet so extremely 
important. I have called this boundary kingdom interme- 
diate between the animal and vegetable kingdoms, and 
connecting both, the Protista (‘ Gen. Morphol./ vol. I, p. 
203 ; vol II, p. xx, p. 403). 
I have, of course, by this separation of the Protista from 
plants on the one side, and from animals on the" other, by 
no means wished to establish an absolute and lasting wall 
of separation between these three organic kingdoms. Rather, 
I consider it very probable that animals as well as plants 
have derived their origin from the Protista, and in fact from 
the simplest Protista, the Monera (1. c. vol. II, p. xx, p. 
403, pi. 1). But provisionally I consider it convenient on 
practical grounds to separate the Protista in the system of 
nature entirely from animals as well as from plants. 
In the systematic introduction to my ‘ Universal Develop- 
ment-history,’ I have distinguished the following eight natural 
groups or “stocks” (Phyla) of the Protista. 
I. Monera. 
1. Gymnomonera (Protogenes, Protamceba, &c.). 
2. Lepomonera (Protomonas, Vampyrella, &c.). 
II. Protoplasta. 
1. Gymnamoebse (Autamoeba, Petalopus, Nuclearia, &c.). 
2. Lepamcebae (Arcella, Difflugia, Euglypha, &c.) 
3. Gregarinae (Monocystidea and Polycystidea). 
III. Diatomaceje. 
IV. Flagellata. 
1. Nudiflagelata (Euglena, Spondylomorum, &c.). 
2. Cilioflagellata (Peridinium, Ceratium, &c.). 
V. Myxoaiycetes. 
VI. Noctiluc.®. 
