TBS TNFUS0RIAN8. 



11 



Chalk is largely made up of the calcareous shel 

 Foraminifera; before il became hardened into rock-masses 

 it was a kind of Foraminifer- 

 ous ooze. 

 Those Rhizopods which 



te a silicions shell are called 

 B idiolaria. A few (Fig. 6) 

 live in fresh-water ponds, but 

 the majority live in the sea. 

 Their shells possess wondrous 

 beauty and variety of orna- 

 mentation. 



Some Rhizopods are known 



develop from little monad- 

 like or round germs, which 

 move about by means of I wo 

 little active threads or tails.* 



Fig 6.—Actino8phtBrium, a Radinla- 



rian 11. ;i morsel of food drawn 



into the cortical layer 6; c. central 



enchymatous body ; ■', 



some balls < if f l-stuff in 1 1 1 • - 



ter; e, pseudopodia of the cortical 

 layer. Highly magnified. 



Glass IT. — G rbu \i;inm>.\. 



General Characters of Gregarines. — These may be I 

 defined as parasitic, worm-like Amoebae. They are long 

 and slender, of quite definite flattened or cylindrical form 

 (Fig. 7) to adapt them to their parasitic life. The larj 

 kind (Gregarina gigantea) is like a piece of fine thread, 

 half an inch long; it lives in the intestine of the lobster. 

 Most Gregarinae are very minute, and are parasites, living 

 in the digestive canal of in 



Class [II. I mi sori \. 



General Characters of Infusoria. - If we allow a little d 

 grass or hay or a piece of fish to stand in a glass of * 

 for a day or two, thus making what is called an infusion, 

 and then examine a drop of this water it will be found to 

 teem with myriads of microscopic creatures, called Infu- 

 Borians, because they are found in infusions. The simplest 

 and minutest form of infusorian is the monad (Fig. 



* Bee Leidy'a Fresh-water Rhizopods of North America, 18 



