192 THE ELEMENTAEY NERVOUS SYSTEM 



ing it mechanically, it shortens slightly and curls orally, 

 as an attached tentacle does. The same is true when it is 

 stimulated by a faradic current. Under this more favor- 

 able method of stimulation a proximal tentacle that had a 

 length of twelve millimeters when at rest shortened to ten 

 on stimulation and curled to a half circle. These reactions 

 disappear after the isolated tentacle has been for five min- 

 utes in seawater containing chloretone and reappear on 

 transferring it for three minutes to pure seawater. 



If an isolated proximal tentacle is cut in two near the 

 middle, the distal piece coils and the proximal piece 

 curves in response to a faradic stimulus as when they 

 were parts of the wiiole tentacle. Both parts, moreover, 

 continue to show slight spontaneous movements as the 

 normal tentacle does. All these responses disappear on 

 anesthetization and reappear after the fragments of ten- 

 tacle have been for a few minutes in pure seawater. 



It is quite evident from these observations that the 

 neuromuscular organization of Corymorplia is most dif- 

 fuse and contains nothing that can rightly be looked upon 

 as centralized. In this respect the hydrozoan polyp is, if 

 possible, more a congregation of parts than the antho- 

 zoan polyp, which lacks very largely that centralization 

 feature that is so characteristic of the neuromuscular 

 structure and activities of the higher animals. 



Among the general activities indicative of the neuro- 

 muscular organization of Corymorplia none are more im 

 portant than feeding. If the contents of the digestive 

 spaces in Corymorptia are examined, they are found to 

 contain, as Torrey (1904 b) has observed, organic detritus 

 composed of the remains of copepods, rotifers, diatoms, 

 and various chlorophyl-bearing protista. The cavity in 

 which these partly digested materials circulate is by no 



