no JELLY-FISH, STAR-FISH, AND SEA-URCHINS. 



to be overspread with a disc of muslin, the fibres 

 and mesh of which are finer than those of the finest 

 and closest cobweb, and if he will imagine the mesh 

 of these fil)res to s^art from these maroinal oranglia, 



he will gain a tolerably correct idea of the lowest 

 nervous system in the animal kingdom. Now, 

 suppose that seven of these eight ganglia are cut 

 out, the remaining one then continues to supply its 

 rhythmical discharges to the muscular sheet of the 



