190 THE ELEMENTARY NERVOUS SYSTEM 



expected, was applied accurately to the stimulated spot. 

 On applying the stimulus directly below the wound the 

 hydranth was turned to that side but never descended far 

 enough to cover the actual region of the stimulus. The 

 failure here seemed to be due to the deficiency in the 

 musculature as a result of the operation rather than to a 

 defect in transmission. Since a decapitated stalk responds 

 to local stimulation in the type of experiment just de- 

 scribed with as much success as a normal one does, it 

 is fair to conclude that, though longitudinal transmission 

 is the predominate feature of the stalk, transverse trans- 

 mission also occurs in this part of Corymorplia. 



This conclusion is supported by the observation that 

 a decapitated stalk which has been partly cut through 

 transversely at several different levels and from several 

 different sides, as Torrey (1904 b) has already described, 

 will nevertheless localize, though incompletely, a stim- 

 ulated point. 



From the observations and experimental results re- 

 corded in this section, it seems fair to conclude that nerv- 

 ous transmission in Corymorplia is very probably limited 

 to the ectoderm and is diffuse, except that in the stalk 

 longitudinal transmission predominates much over trans- 

 verse. Notwithstanding this primitive state of nervous 

 development, reactions that have all the essentials of a 

 nervous reflex may occur. Thus, when a proximal ten- 

 tacle is vigorously stimulated, not only do it and some of 

 the adjacent tentacles respond, but the proboscis com- 

 monly turns toward the point of stimulation. This ac- 

 curate form of response of a distantly located organ to 

 a circumscribed stimulus has all the characteristics of a 

 reflex, though it is probably dependent upon the activities 

 of a nerve-net that has the capacity of calling into action 



