236 CCELENTERATA 



(7) Symmetry. Is this animal asymmetric, radially or 

 bilaterally symmetric, or is it both radially and 

 bilaterally symmetric? 



2. The Appendages, or Tentacles. 



(1) Number? 



(2) Shape? 



(3) Are they hollow or solid? 



(4) Where and how are they arranged? 



3. Locomotion and Motion. In the Coelenterates there is a 

 differentiation of muscle-cells and unstriped muscle-fibers. 



(1) Has this animal any locomotion? If so, how is it 



accomplished? By body movement, or by move- 

 ment of appendages, or by both? Describe accu- 

 rately the successive steps in locomotion. 



(2) What motions — aside from locomotion — has this 



animal? 

 Place a tiny particle of meat on the tip of a tentacle. 

 What does the tentacle do? Put the meat at the 

 base of the tentacle. What happens? 



(3) The skeleton is the passive system of motion and loco- 



motion in the higher forms. 



(a) Does this animal have a skeleton? If so, of what 



does it consist? 



(b) What is its purpose? 



4. The Nutrition of the Animal. 



(1) What is its food? How is it obtained? 



(2) Is there any vestige of a tube or gullet dipping down 



from the mouth into the body cavity? 



(3) Are there any divisions of the gastrovascular cavity? 



Do the tentacles have any communication with the 

 cavity? 



(4) How and where are the processes of digestion, circula- 



tion, and respiration carried on? Where is the waste 

 ejected? 



(5) Is there any advancement in the work of nutrition over 



that in the Amoeba and sponge? If so, what? 



5. Multiphcation. 



(1) The hydra is hermaphroditic. Near the tentacles, look 

 for small, conical projections. These are the sper- 



