SECTION OF COVERED-EYED MEDUS&. it 
Lastly, the third mode of section is represented 
in the next cut. Here seven of the marginal ganglia 
having been removed as before, the eighth one was 
made the point of origin of a circumferential section, 
which was then carried round and round the bell in 
the form of a continuous spiral—the result, of course, 
being this long ribbon-shaped strip of tissue with 
the ganglion at one end and the remainder of 
the swimming-bell at the other. Well, as before, 
the contraction-waves always originated at the 
ganglion; but now they had to course all the way 
along the strip until they arrived at its other ex- 
tremity; and, as each wave arrived at that extremity, 
it delivered its influence into the remainder of the 
swimming-bell, which thereupon contracted. Now, 
in this experiment, when the spiral strip is only 
made about half an inch broad, it may be made 
more than a yard long before all the bell is used up 
in making the strip; and as nothing can well be 
imagined as more destructive of the continuity of 
a nerve-plexus than this spiral mode of section 
must be, we cannot but regard it as a very remark- 
able fact that the nerve-plexus should still continue 
to discharge its function. Indeed, so remarkable does 
this fact appear, that to avoid accepting it we may 
well feel inclined to resort to another hypothesis, 
namely, that these contraction-waves do not depend 
for their passage on the nervous network at all, 
but that they are of the nature of the muscle-waves, 
or of the waves which we see in undifferentiated 
protoplasm, where all parts of the mass being equally 
excitable and equally contractile, however severely 
