Tae MicroscopicaL Nrws 
AND 
NORTHERN MICROSCOPIST. 
No. 33. SEPTEMBER. 1883. 
HYDRA: ITS ANATOMY AND DEVELOPMENT. 
By J. W. DUNKERLEY. 
MONG the many myths which have come down to us from 
f ancient times, there is one which says a monster with many 
heads, called the Hydra, infested the Lake Lerna. According to 
one authority (Diodorus) it had roo heads; according to another 
(Simonides) it had but 50; while according to Apollodorus only 
g heads. It was said that as soon as one of these heads was cut 
off two others immediately grew in its place. It was one of the 
labours of Hercules to destroy this monster; and this he effected, 
with the help of Iolaus, who applied a burning iron to the wounds 
as soon as the animal was decapitated. The mention of an animal 
so much like the minute creature common to our ponds, that 
zoologists have given it the name of Hypra, suggests that there 
might at one time have lived a much larger specimen than the one 
with which we are familiar, and which excited the wonder of the 
observers of former times; but it is doubtful whether it was large 
enough to be at all dangerous, and modern thought leads to the 
suggestion that the so-called labours of Hercules was simply one of 
those beautiful myths, founded on some known fact, by means of 
which the higher moral truths were inculcated in the past ages. 
This little animal, the Hydra, was one of the first-fruits of 
microscopical research, and has been studied by a number of 
eminent men; it has probably had more papers written upon it 
than any other animal in existence. Leeuwenhoek, who was a 
close observer of nature, first took notice of it in the year 1703, 
and observed the uncommon way in which its young were pro- 
duced. An account was communicated by him to the Royal 
Society, and made public in the 283rd number of the Philosophical 
Transactions. But its more amazing peculiarities were reserved for 
the inquisitive and happy genius of Trembly to discover, in the 
year 1739. ‘This latter observer met with the Polype in his searches 
VOL, . III. : 
