GEANTIA V3 



Can you decide whether or not the branches of 

 Spongilla move ? "With a very fine bristle care- 

 fully touch the surface of the body-substance, 

 several times if necessary, in the neighborhood 

 of an osculum. Do you detect any change in 

 the latter ? Does it open wider or close ? Can 

 Spongilla feel ? 



Put a fragment of the body-substance of living 

 Sfongilla under the microscope, and note the 

 motions of the amoeboid and flagellate cells. 



l. Ingestion. — Sift some particles of finely powdered 

 chalk, indigo, or carmine into the water contain- 

 ing living Spongilla, and look through the water 

 towards the light to see whether the particles 

 are drawn into the oscula or washed away from 

 them ? Can you from your own observations 

 explain why the current of water flows in this 

 direction ? What, then, seems to be the function 

 of the oscula ? 



General Questions. — Is there anything about the 

 structure or mode of life of Spongilla which would lead 

 you to suppose that it might be used as food or de- 

 stroyed in other ways by water animals ? If so, has it 

 any means of protection against them? By what means 

 may it be distributed through lakes and rivers ? 



Example 3. — Grantia {8p.) 



Material. — Students living along the New England 

 coast can obtain this sponge in the living condition, in 

 which case some points in its physiology may be studied 

 as indicated for Spongilla. It is especially valuable, 



