94 PROTOZOA. 
At any time Vorticella is capable of breaking free from its stalk and 
swimming away, and it can also encyst, in which condition it may, like 
Ameba, experience considerable vicissitudes with impunity. 
Conjugation is effected by one individual setting free by budding a 
number of small buds which acquire a second band of cilia and swim away. 
One of these settles upon another individual and interchange of 
nuclear material is effected. The bud is said to then atrophy, the total 
result being the transfer of nuclear material from one individual to 
another. In this respect the conjugation of Vortccella more nearly re- 
sembles the sexual reproduction of AZefazoa. 
Vorticella belongs to the same class as Paramecium (Ciliata) but 
to the order Perdtracha, the cilia being confined to 9 ring around the 
mouth. 
IV.—GREGARINA. 
SuB-KINGDOM - PROTOZOA. 
PHYLUM CORTICATA. 
CLass SPOROZOA. 
Gregarina blattarum is a small animal found in 
part of the intestine (the mesenteron) of the common 
Cockroach (B/atia). Hence it is an endopara- 
site. Its body is elongated and has a definite 
shape. In the protoplasm there can be discerned an outer 
cortex which appears to be more or less contractile and an 
inner more fluid medulla: The cortex secretes a thin cuticle 
which envelopes the body. At one end, usually 
regarded as the anterior end, the cuticle is 
thickened into a cap with a rim of hooks, At about one- 
third of the length of the body from the anterior end, the 
cuticle extends a as thin septum or partition across the 
protoplasm, dividing the body into an anterior protomerite 
and a posterior deutomerite. In the medullary substance 
of the deutomerite is an oval nucleus and occasionally there 
can also be seen a small nucleolus. 
There are no cilia nor pseudopodia and the animal can 
progress only slowly by a creeping movement of the cortex. 
There is no mouth nor anus, and no solid food 
: passes into the body of the animal. Gvegarina 
1s, from its habitat, surrounded on all sides by soluble and 
diffusible proteids which have been prepared by its host, the 
cockroach, for its own use. These are absorbed by G7e- 
garina through the cuticle as required. There appears to 
Habit. 
Structural. 
Alimentary. 
