Protozoa. 



yellow cells are found scattered through the body in 

 almost all species. 



In size these Radiolarians are from \ to -gj^th of 

 an inch in diameter, the larger forms, however, are 

 not single individuals but clusters united into compact 

 colonies, each component individual having its own 

 central capsule. Most of these are found floating on 

 or in the waters of the sea. Some oceanic forms have 

 no skeleton, and are described under the name sea- 

 glue (Thatassicolla). 



Some allied forms, destitute of central capsule and 

 of yellow cells, are found in fresh- water bog pools in 

 this country. 



CHAPTER V. 



SUB-KINGDOM i : PROTOZOA continued. 



Class 5. Infusoria. If we place under the micro- 

 scope, water in which animal or vegetable matter has 

 been infused for six cr 

 seven days, especially in 

 warm weather, we see that 

 the fluid contains minute, 

 actively moving creatures 

 ranging in size from ^V tri 

 to the T^Vfrth of an inch 

 in length. They are 

 mostly oblong in shape 

 and their rapid locomo- 

 tion is due to the action 



c f- ., ., ... , v Three Ciliated Infusoria. 



Of fine Vlbratlle Cilia which A> Ox ytrichaf>ibba. B. Trachelocerca 



clothe, either the whole bice * s - c - Vorticella ' citrin - 



FIG. 13. 



