ANIMALCULES 499 



than in animals. Before these can be formed two individuals 

 must together be surrounded by a firm coating or cyst, and 

 they then break up into a multitude of little spores surrounded 

 by firm coats. The spores become free by a somewhat complex 

 process, the firm coat of each then ruptures, and the contained 

 protoplasm emerges, ultimately growing into an adult Gregarine, 

 which is at first imbedded in and nourished by one of the cells 

 lining the intestine of the cockroach. 



The Sporozoa not only include many forms more or less 

 similar to the one described, but also a large number of much 

 simpler species, parasitic in the cells of Vertebrates and other 

 higher animals. 



END OF VOL. I 



