Il8 COELENTERATES 



teric canal? How far do the others extend? Make out the 

 primaries, the secondaries and tcrtiaries. How many of 

 each? What seems to be their function? 



Make an enlarged drawing of the base of the animal 

 showing the arrangement of the septa (X2). 



Look on the inside of the mesenteries for muscles, small 

 strips about midway between the mesenteries. Between the 

 mesenteries are found the reproductive organs, the excretory 

 organs and circulatory fluid which nourishes the body, which 

 is composed of the digested food and sea water. This is 

 circulated principally by the movements of the body. 



Enumerate the motions of the anemone which you think 

 possible from its form and structure. 



The Coral. — Study the common star coral and see if 

 you can trace any relation between the framework of the 

 coral and the plan of the sea anemone. 



Explain the relation, if any be found, and discuss the pro- 

 cess of coral building and reef making. 



THE FRESH WATER HYDRA 

 Hydra fusca 



Specimens of fresh-water hydra may usually be obtained 

 in pools of water near the school and because of their gen- 

 eral distribution are good forms for study. The living forms 

 may be watched in a basin of water, and then hardened in 

 alcohol for sectioning. 



(i) Note the general form of the animal. Find tlfe J>o(fy, 

 the tentacles and the base. Can you make out a definite struc- 

 ture to the outside of the body? If possible find one with 

 buds growing from the side. Note the number, arrange- 



