CHAPTER IV. 



KXPERIMENTS IN SECTION OF COVEllED-EYED MEDUSA 



Amount of Section which the Neiiro-muscular 

 Tissues of the Medusoe will endure without 

 suffering Loss of their Physiological Continuity. 



The extent to which the neuro-muscular tissues 

 of the Medusa may be mutilated without under- 

 going destruction of their physiological continuity is 

 in the highest degree astonishing. For instance, to 

 begin with the covered-eyed Medusae, I shall briefly 

 state three modes of section, the results of which serve 

 to show in a striking manner the fact in question. 



The annexed woodcuts represent the umbrella of 

 Aurelia aurita, with its manubrium cut off at the 

 base, and the under or concave surface of the 

 umbrella exposed to view, shewing in the centre 

 the ovaries, and radiating from them the branched 

 system of nutrient tubes. The umbrella when 

 fully expanded, as here represented, is about the 

 size of a soup plate, and, as previously stated, all 

 the marginal ganglia are aggregated in the eight 

 marginal bodies or lithocysts. Therefore if the 

 reader will imagine the first of the diagrams (Fig. 8) 



