CHAPTER V. 



EXPERIMENTS IN SECTION OF NAKED-EYED MEDUSAE. 



Distribution of Nerves in Sarsia. 



My experiments have shown that the nervous 

 system in the naked-eyed Medusse is more highly 

 organized, or integrated, than it is in the covered- 

 eyed Medusae ; for whereas in the latter I obtained 

 no evidence of the gathering together of nerve- 

 fibres into definite bundles or trunks (the plexus 

 being evenly distributed over the entire surface of 

 the neuro-muscular sheet lining the umbrella), in 

 the former I found abundant evidence of tliis 

 advance in organization. And as the experiments 

 in this connection serve to substantiate the histo- 

 logical researches of Professors Haeckel, Schultz, 

 Eimer, and Hertwig, in as far as the distribution of 

 the main nerve-trunks is concerned, I shall here 

 detail at some length the character and results of 

 these experiments in the case of Sarsia. 



The occurrence of reflex action in Sarsia is of 

 a very marked and unmistakable character. I may 

 begin by stating that when any part of the internal 

 surface of the bell is irritated, the manubrium 

 responds; but as there is no evidence of ganglia 



