PROTOZOA 33 
The bud, or buds, are formed in the floor of this cavity. 
When they leave the 
parent they are ciliated ; 
a fact which lends support 
to the view that the Acine- 
taria are descended from 
the Cihata. 
lead a wandering life, but 
after a time settle down, 
lose their cilia, and acquire 
tentacles. 
Chass V. Sporozoa. 
The members of this 
class are all parasitic; and 
correlated with this condi- 
tion of life is the absence 
of locomotor organs, the 
absence of any mouth,— 
the nutriment being ab- 
sorbed all over the body,— 
and a reproductive process 
which results in the forma- 
tion of a very large number 
of young. The nucleus is 
always single even when the 
cell is divided into two 
chambers. No contractile 
vacuole is present. The 
cortical layer of protoplasm 
may show traces of fibrilla- 
tion. 
Of the four sub-classes 
which compose this class, 
that of the Gregarinidea 
is the most important. The 
true Gregarines, with very 
They at first 
. Knobbed tentacles. 
. Membranous shell. 
. Nucleus. 
Fic. 26.—Acineta grandis, Sav. Kent. 
Stalk. 5. An example of 
Acineta lemnarum, 
showing relative size 
of the two species. 
few exceptions, pass their early life as cell parasites, afterwards 
3 
