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will do the same for them, and enable them to be grown success- 
fully without nitrogenous manures ? 
A brief discussion followed, in which Dr. FitzGerald, Mr. Walton, 
and others took part, and a cordial vote of thanks to the President 
for his excellent paper was passed, The next meeting will take 
place on the first Tuesday in November, when Mr. Henry Ullyett 
will read a paper on the ‘“‘ Evolution of the Horse.” 
A short discussion ensued and a hearty vote of thanks proposed 
by Dr. Fitz-Gerald was carried. About sixty members were present. 
Novemser 13th, 1894. 
Fifty members and friends were present. The following paper 
on the Life History of the Frese Water Hypra, written by Miss 
Knight was read by Mr. Knight. It was well illustrated by 
diagrams and was followed by a discussion. 
THE FRESH-WATER HYDRA—Hydra viridis. 
There is an old story of the Greeks, in which we were 
interested in our school days, which tells us that there was a 
celebrated monster to which the name of Hydra was given which 
infested the neighbourhood of Lake Lerna. It had a hundred 
heads according to Diodorus, and as soon as one was cut off two 
immediately grew up unless the wound was cauterized. It was 
one of the labours of Hercules to destroy this monster, which he 
accomplished. 
The modern hydra probably obtained its name from this fable, 
but it was quite a different sort of animal, although at one time its 
story created as much excitement in the scientific world, as that 
of the monster Hydra could have done amongst the Greeks. The 
little animal to which this name is applied can be regarded as the 
type of the third sub-kingdom of animals, that known as 
Calenterata ; which include jelly fishes and sea-anemones, animals 
having a stomach cavity and a body cavity as an out-growth there 
from, and a radiate symmetry; also a mouth bordered with 
tentacles armed with thread cells. It is very commonly found in 
ponds and ditches, adhering to aquatic plants. Ifa tuft of water 
crowfoot be placed in a vessel of water exposed to the light it is 
most probable that in half an-hour we should see the Hydra in.its 
native element. It does sometimes attain nearly an inch in 
length, but is rarely more than half an inch, it possesses a 
cylindrical body having a mouth at one end, and a disc at the 
other for voluntary attachment. Around the mouth are 6, 7, or 
even 10 slender contractile arms, radiating from the body like a 
star, moving up and down in all directions, and then retracting 
until the animal seems to be a mere mass of jelly; then in an 
instant all is activity again. 
