106 PHYLUM PROTOZOA—THE SIMPLEST ANIMALS. 
and attacking the lining epithelium recommence the life 
history. 
GENERAL CLASSIFICATION OF PROTOZOA 
Since the Protozoa are unicellular organisms (except the 
few which form loose colonies), their classification should 
be harmonious with that of the cells in a higher animal. 
This is so. Thus (a) the Rhizopods, in which the living 
matter flows out in changeful threads or “‘ pseudopodia,” as 
CLASSIFICATION OF PROTOZOA 
{CorTICATA.) (GYMNOMYXA.) (CORTICATA.) 
Predominantly F Predominant] 
ciliated and ey encysted nat 
active. passive. 
INFUSORIANS. RHIZOPODS. SPOROZOA. 
ACINETARIA. RADIOLARIA. 
FORAMINIFERA. 
CILIATA. SPOROZOA 
LABYRINTHULIDEA, 
RHYNCHOFLAGELLATA 
HELI0z0A. OR 
DINOFLAGELLATA. 
LOBOSA. 
GREGARINES. 
FLAGELLATA. 
PROTEOMYXA and MyYcETOzOA, 
PRIMITIVE FoRMS. 
in the common Ameba, are comparable with the white 
blood corpuscles or leucocytes, many young ova, and other 
“ameboid” cells of higher animals; (4) the Infusorians, 
which have a definite rind and bear motile lashes (cilia 
or flagella), e.g. the common Paramecium, may be likened 
to the cells of cé//ated epithelium, or to the active sperma- 
tozoa of higher animals; (c¢) the parasitic Sporozoa, which 
