SYSTEMATIC SURVEY. 107 
have a rind and no motile processes or outflowings, may 
be compared to degenerate muscle cells, or to mature ova, 
or to “‘excysted” passive cells in higher animals. 
This comparison has been worked out by Professor Geddes, who also 
points out that the classification represents the three physiological 
possibilities—(a) the amoeboid units, neither very active nor very passive, 
form a median compromise; (4) the ciliated Infusorians, which are 
usually smaller, show the result of a relative predominance of expendi- 
ture; (c) the encysted Gregarines represent an extreme of sluggish 
passivity. \ 
But, as Geddes and others have shown, the cells of a higher animal 
often pass from one phase to another,—the young amceboid ovum 
accumulating yolk becomes encysted, the ciliated cells of the windpipe 
may, to our discomfort, sink into amceboid forms. The same is true of 
the Protozoa ; thus in various conditions the ciliated or flagellate unit 
may become encysted or amceboid, while in some of the simplest forms, 
such as Protomyxa, there isa ‘‘ cell-cycle ” in which all the phases occur 
in one life history. 
SYSTEMATIC SURVEY 
A. Primitive forms.—Under this heading may be included two 
classes : (1) the Proteomyxa, primitive, insufficiently known forms often 
without a nucleus, though nuclear material may be present in the form 
of scattered granules (chromidia), and (2) the Mycetozoa, organisms 
with somewhat complex fructifications, often classed as plants allied 
Fic, 48.—Diagram of Protomyxa aurantiaca.—After Haeckel. 
x. Encysted; 2. Dividing into spores; 3. Escape of spores, at first 
flagellate, then amceboid ; 4. Plasmodium, formed from fusion of 
small amoebz. 
to Fungi. As examples of the Proteomyxa, we have the interesting 
Protomyxa in four phases: (a) encysted and breaking up into spores, 
which (4) are briefly flagellate, (c) sink into amceboid forms, and (d) 
flow together into a composite ‘‘ plasmodium ” ; Vampyrella, parasitic 
on fresh-water Algz ; and many others. 
The Mycetozoa are well illustrated by Fudigo or 4thalium septicum, 
“¢ flowers of tan,” found in summer as a large plasmodium on the bark 
of the tan-yard. The coated spores are formed in little capsules which 
rise from the surface of the plasmodium. The spores may be first 
flagellate, then amceboid, or amoeboid from the first ; the characteristic 
plasmodium is formed by the fusion of the amcebee, 
