SECTION OF COVERED-EYED MEDUSA. 



69 



the outer circle, of course, continued its contractions 

 as before. Now, the neck of tissue at z measured 

 only one-eighth of an inch across, while the ring of 

 tissue {y z), when cut through and straightened °out 



Fig. 10. 



upon the table, measured one inch across and sixteen 

 inches in length ; that is to say, sixteen square inches 

 of tissue derived its impulse to vigorous contrac- 

 tions through a channel one-eighth of an inch wide. 



