THE MARINE AQUARIUM. 83 
crenated lips, of a pellucid softness that would appear as 
if chiselled out of alabaster, were they not constantly 
varying their form, and every instant undergoing a new 
“‘ sea-change.”’ The tentacles are very regularly arranged 
around the mouth, but towards the margin they thicken 
and thicken till they form a dense fringe that overlaps the 
column, and continues ever waving as if stirred by 
trembling ocean currents. If I now strike the glass with 
my finger, or even breathe lightly on the surface of the 
water, they are all withdrawn, the stately column shrinks 
down into a mass of pulp, and in a few moments swells 
out like a globular balloon, so tight and large that one 
momentarily expects it to burst. For an instant only it 
remains thus blown out; it is suddenly constricted as if 
clasped by a cord, and it then becomes double like a pair 
of globes placed one upon the other, and flattened where 
they meet. Suddenly the imaginary girdle slips down- 
ward, disappears, then it contracts, rises again, assumes 
its noblest proportions, expands its thousand fringes, all 
delicately waving above the dark stones, and is once more 
as lovely, or lovelier than ever. 
This has been described as one of the most tender of 
its class, but I have long been convinced that it is com- 
paratively hardy, and may be preserved with very great 
certainty. So long as the water is kept moderately pure, 
by an occasional filtering through charcoal—which aerates 
and purifies at the same time—it lives and prospers, 
occasionally moving from place to place, but almost 
always expanded, and every instant assuming some new 
form. It is, however, so far delicate that, if frequently 
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