90 
ZOOPHYTA HYDROIDA. 
cupied. A bead springs from the remaining stem, cut, over very 
near the root; and a redundance of heads may be obtained from 
artificial sections, apparently beyond the ordinary provisions of 
nature. Thus twenty-two heads were produced through the 
course of 550 days, from three sections of a single stem.”* The 
observations of Mr Harvey on the same, or a very nearly allied, 
species of zoophyte confirm the experiments of Sir J. G. Dal * 
yell, so far as these have reference to the deciduousness of the 
polypes and their regeneration ; *)* and it seems to me not alto- 
gether unwarrantable to infer a like temporary existence and re- 
vival in those of the Sertulariadse from a reflection on the ex- 
periments of Mr Lister, — incomplete certainly, but which prove 
that under certain circumstances their polypes disappear by a pro- 
cess of internal absorption, £ and under convenient circumstances 
would probably have been renovated, as I have witnessed this re- 
sult in similar experiments. On Saturday, May 28th 1837, a spe- 
cimen of Campanularia gelatinosa was procured from the shore, 
and after having ascertained that the polypes were active and entire, 
it was placed in a saucer of sea-water. Here it remained undis- 
turbed until Monday afternoon, when all the polypes had disap- 
peared. Some cells were empty or nearly so, others were half-fil- 
led with the wasted body of the polype, which had lost, however, 
every vestige of the tentacula. The water had become putrid, and 
the specimen was therefore removed to another vessel with pure 
water, and again set aside. On examining it on the Thursday, 
* Edin. New Phil. Journ. xvii. p. 415. 
t “ The most singular circumstance attending the growth of this animal, and 
which I discovered entirely by accident, remains to be mentioned. After I had 
kept the clusters in a large bowl for two days, I observed the animals to droop 
and look unhealthy. On the third day the heads were all thrown off, and lying 
on the bottom of the vessel ; all the pink colouring matter was deposited in the 
form of a cloud, and when it had stood quietly for two days, it became a very 
fine powder. Thinking that the tubes were dead I was going to throw them 
away, but I happened to be under the necessity of quitting home for two days, 
and on my return I found a thin transparent film being protruded from the top 
of every tube : I then changed the water every day, and in three days time every 
tube had a small body reproduced upon it. The only difference that I can dis- 
cover in the structure of the young from the old heads, consists in the new ones 
wanting the small red papilla, and in the absence of all colour in the animal.” 
— Proceed. Zool. Soc. No. 41, p. 55. 
f Phil. Trans. 1834, p. 374, 376. 
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