GREGARINIDA. -INFUSORIA. 



FIG. 4. Flint-shelled Radiolarian 

 {Heliospluera). 



vision within the shell, the 

 young at first resembling 

 little oval bodies, with hair- 

 like tails. 



VALUE. The shells of the ma- 

 rine forms fall in a shower upon 

 the bottom, and form chalk-beds, 

 as the Dover cliffs, in England, 

 thus adding to the land of the 

 globe. The stone of the Pyramids 

 is made up of fossil Foraminirera. 



Specimens for Study. 

 The Amoeba can be found 

 on leaves in fresh-water 



ponds. Foraminifera can be caught with a fine net in the 

 ocean, or found in pools at low tide. The shells can be 

 ground and mounted for the microscope. 



Class III. GREGARINIDA. 



General Characteristics. These (Fig. 5) are minute 

 forms that take up their abode in lobsters, crabs, beetles, 

 cockroaches, worms, and other animals, 

 and lead a parasitic life, existing upon 

 the juices of the animals they inhabit. 

 They resemble minute worms ; one, 

 found in the European lobster, half an 

 inch in length, is called Gregarina gi- 

 gantea, being the largest single-celled 



animal knQwn Th unde rgO Several 

 J 



curious changes before reaching mature 



growth. 



FlG^.-Gregarinaof 

 Nemertes Gessert- 



ensis, showing nu- 



cleus and granules. 



Class IV. INFUSORIA. 



General Characteristics. Animals of permanent form 

 with cilia, or hair-like organs, for locomotion and procur- 

 ing food. They are either free or stalked. 



