THE ACTIVITIES OF CORYMORPHA 319 



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 whole ten- 

 tacle. Both parts, moreover, continue to show slight spontane- 

 ous movements as the normal tentacle does. All these responses 

 disappear on anesthetization and reappear after the fragments 

 of tentacle have been for a few minutes in pure sea-water. 



It is quite evident from these observations that the neuro- 

 muscular organization of Corymorpha is most diffuse and con- 

 tains nothing that can rightly be looked upon as centralized. 

 In this respect the hydrozoan polyp is, if possible, more a congre- 

 gation of parts than the anthozoan polyp, which, as I have 

 elsewhere attempted to show (Parker, '17 b), lacks very largely 

 that centralization feature that is so characteristic of the 

 neuromuscular structure and activities of the higher animals. 



5. LOCOMOTION 



Although Corymorpha is usually described a? a fixed polyp, 

 it possesses, as Torrey ('04 a, p. 416) has shown, some slight 

 powers of locomotion. When the buried end of a Corymorpha 

 normally affixed in the mud is carefully examined, it is found to 

 be more or less ensheathed in a tube of its own secretion. If 

 such an animal is freed from the surrounding sand and mud and 

 is placed on a small glass plate, it soon attaches itself by the 

 secretion of a new tube and by its frustules and moves slowly 

 along producing new tube material as it goes. The highest rate 

 of locomotion that I have ever observed is seven millimeters in 

 twenty-four hours, though Torrey ('04 a, p. 416; 1907, p. 278) 

 has recorded about twice that amount in the same length of 

 time. In any event the rate is relatively low and the animal is 

 essentially fixed. I have made no observations on the method 

 of locomotion. The rate favors Torrey 's view ('04 a, p. 415) 

 that this process is accomplished by the amoeboid activity of the 

 basal ectoderm, a procedure that is claimed to occur in Hydra 

 and is probably employed by the larva of Corymorpha as it 

 creeps out of its egg capsule (Torrey, '07, p. 259). 



