458 'Journal of Comparative Neurology and Psychology, 



First, as to the cause of the surface reaction of Gonionemus, Mr. 

 Morse states, incorrectly, that I believe the reaction to be due to 

 light. As a matter of fact, I have said, and have attempted to 

 show that, although light seems to be one of the important condi- 

 tions for this reaction, it may occur in the absence of light. My 

 view concerning the reaction, together with one of my chief 

 grounds for holding the view, are expressed in the following 

 quotation from one of my papers : " In sunlight the medusae at first 

 come so forcibly to the surface that half the bell may appear above 

 the water. Usually a bell thus forced out of the w^ater inclines 

 slightly to one side, and thus tends to turn the animal over, so that 

 the observer can never be quite sure whether the turning is due 

 altogether to the action of gravity, or whether it is in part due to 

 some peculiarity in the final contraction of the bell. After having 

 been in sunlight for a few minutes, the animals come to the surface 

 with noticeably less impetus, and soon they fail to reach the 

 surface at all. But even in the latter case they turn over, just as 

 they do in ordinary light after reaching the surface. Under these 

 conditions the turning due to stimulation by light evidently is 

 accomplished by bell contractions."^ And I further add, in an 

 attempt to account for the inhibitory influence of light, "Light 

 having been one of the most important stimuli for the initiating of 

 the surface reaction; i.e., turning, inhibition of activity, expansion 

 of organs, may finally have come to be the cause of a very similar 

 reaction in the presence of other conditions, so that increase in 

 light intensity now uniformly causes an active Gonionemus to 

 expand fully for a few seconds and permit itself to sink passively."^ 



As Mr. Morse, without contradicting any of my statements of 

 fact and without ofl^ering further facts or suggesting an explanation 

 of the surface reaction of Gonionemus, simply questions the cor- 

 rectness of the partial account of the phenomenon which I have 

 given, I can not do otherwise than hold to my earlier view of the 

 matter. 



On p. 3 of Mr. Morse's paper attention is called to certain 

 "paradoxical facts" in my work which demand further investiga- 

 tion. These facts, or better statements, are numbers 2 to 5 of the 

 above list of points in which Mr. Morse disagrees with me. The 



^Amer. Jour, Physiol., Vol. 9, p. 285. 1903. 

 "^Amer. Jour. Physiol, Vol. 9, p. 288. 



