16 STUDIES OF ANIMAL LIFE. 



2. Ihe Canal System. 



a. Identify the oscula and inhalent pores ? 



b. Try to trace canals from the inhalent pores to 

 the central cavities. (Use a split sponge.) 



3. Examine a few fibers torn from the skeleton. 



a. What is their appearance and arrangement ? 

 h. What is their composition ? (Burn a bit for the 

 odor.) 



4. Make a drawing of some of these fibers. 



5. In this sponge what corresponds to the spicules of 



Grantia and Spongilla ? 



Suggestive Questions. 



1. Where are toilet sponges obtained? How are they 



gathered and prepared for market ? 



2. Are sponges ever free-swimming animals ? 



3. What do sponges eat ? 



4. How do they obtain their food ? 



5. Must they breathe ? 



6. Are sponges protected from their enemies ? 



7. Classify sponges according to the kind of skeleton. 



8. How do you know sponges are animals ? 



