PROTOZOA 



6l 



ture, the so-called " collar," which is found practically 

 nowhere else except on certain cells in sponges (Figs. 6, 



FIG. 5. Dinobryotti portion 

 of the motile colony show- 

 ing zooids, each in its own 

 lorica. Much magnified. 



FIG. 6. Codosiga: f, fla- 

 gellum ; c, " collar" ; b t 

 body ; n, nucleus ; cz>, 

 contractile vacuole ; nv, 

 nutritive vacuole. Much 

 magnified. 



'CLASS 4. Sporozoa 

 > 



The Sporozoa are all parasitic, and are found in va- 

 rious parts of the bodies of fishes, frogs, turtles, insects, 

 crustaceans, worms, and so on, some living in the 

 digestive organs, others in glands, while still others 

 penetrate into the muscle fibers of the infested animal 

 (Fig. 7). They have no organs of locomotion, but move 

 by wormlike contortions of the body. The protoplasmic 

 body substance is covered by a cuticle, and contains a 

 nucleus (Fig. 8). Liquid food is absorbed through the 

 cuticle (Fig. 7). 



