I22 THE OCEAN WORLD. 
pieces into which it has been divided.” ‘The same polyp,” says 
Trembley, ‘‘ may be successively inverted, cut in sections, and turned 
back again, without being seriously injured.” 
If a green Hydra is cut into two pieces, and the stomach is 
cut off in the operation, the voracious creature will, nevertheless, 
continue to eat the prey which presents itself. It gorges itself with 
the food, without troubling itself with the loss which it has sustained ; 
but the food no longer nourishes it, for it merely enters by one 
opening, passes through the intestinal canal, and escapes by the 
other. It realises Harleville’s pleasantry of M. de Crac’s horse, in 
the piece of that name, which eats unceasingly, but never gets any 
fatter. 
All these instances of mutilation, resulting in an increase of life, are 
very strange. The naturalists to whom they were first revealed could 
scarcely believe their own eyes. Réaumur, who repeated many of 
Trembley’s experiments, writes as follows: “ I confess that when I saw 
for the first time two polyps forming by little and little from that 
which I had cut in two, I could scarcely believe my eyes ; and it isa 
fact that, after hundreds of experiments, I never could quite reconcile 
myself to the sight.” 
In short, we know nothing analogous to it in the animal kingdom. 
About the same period Charles Bennet writes: “We can only judge 
of things by comparison, and have taken our ideas of animal life from 
the larger animals ; and an animal which we cut and turn inside out, 
which we cut again, and it still bears itself well, gives one a singular 
shock. How many facts are ignored, which will come one day to 
derange our ideas of subjects which we think we understand! At 
present we just know enough to be aware that we should be surprised 
at nothing.” 
Notwithstanding the philosophic serenity which Bennet recom- 
mends, the fact of new individuals resulting from dividing these 
fresh-water polyps was always a subject of profound astonishment, 
and of never-ending meditation. 
CoRYNIDA. 
We have already said that recent researches have led to a separa- 
tion of this class of animals from the Sertularide, and to their being 
formed into an order by themselves, Of these creatures we formerly 
only knew one of the forms, namely, the polyp form; or, rather, the 
first stage of it. During their earliest days they possess a polyp, fur- 
nished with tentacles, and a bell-shaped body. During their medusoid 
