THE LIFE OF THE SIMPLEST ANIMALS 15 
food of Gregarina is the liquid food of the host as it exists 
in the intestine, and which is simply absorbed ‘anywhere 
through the surface of the body of the parasite. There is 
no mouth opening nor fixed point of ejection of waste 
material, nor is there any contractile vacuole in the body. 
In the method of multiplication or reproduction Gre- 
garina shows an interesting difference from Ameba and 
Paramecium and Vorticella. When the Gregarina is 
ready to multiply, its body, which in most species is rather 
elongate and flattened, contracts into a ball-shaped mass 
and becomes encysted—that is, becomes inclosed in a tough, 
membranous coat. This may in turn be covered externally 
by a jelly-like substance. The nucleus and the protoplasm 
of the body inside of the coat now divide into many small 
parts called spores, each spore consisting of a bit of the 
cytoplasm inclosing a small part of the original nucleus. 
Later the tough outer wall of the cyst breaks and the 
spores fall out, each to grow and develop into a new Gre- 
garina. In some species there are fine ducts or canals 
leading from the center of the cyst through the wall to the 
outside, and through these canals the spores issue. Some- 
times two Gregarine come together before encystation and 
become inclosed in a common wall, the two thus forming a 
single cyst. This isa kind of conjugation. In some spe- 
cies each of the young or new Gregarine coming from the 
spores immediately divides by fission to form two indi- 
viduals. . 
8. Marine Protozoa.—If called upon to name the char- 
acteristic animals of the ocean, we answer readily with the 
names of the better-known ocean fishes, like the herring and 
cod, which we know to live there in enormous numbers; the 
seals and sea lions, the whales and porpoises, those fish-like 
animals which are really more like land animals than like 
the true fishes; and the jelly-fishes and corals and star-fishes 
which abound along the ocean’s edge. But in naming only 
these we should be omitting certain animals which in point 
