THE SIMPLEST ANIMALS OR PROTOZOA 29 



fixed point of ejection of waste material., nor is there any 

 contractile vacuole in the body. 



In the method of multiplication or reproduction (ire- 

 garina shows an interesting difference from Amceba and 

 ParamoBcium and Vorticella. When the Gregarina is 



A 



FIG. 11. Gregarinidae. A, a Grcgarinid (Actinocephalus oligacanthus) from the in- 

 testine of an insect (after STEIN) ; B and C, spore forming by a Gregarinid (Coc- 

 cidium oviforme) from the liver of a guinea-pig (after LEUCKART) ; D, E, and F, 

 successive stages in the conjugation and spore forming of Gregarina polymorpha 

 (after KOELLIKER). 



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 Ore- 



