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LEEUWENHOEK AND HIS “LITTLE ANIMALS” 
animalcules’* (which are flat beneath, and roundish above, 
and which I have discovered in most other kinds of water, 
and which are hardly a thousandth of the size of the 
animals which they crawl on with their little feet, and 
cause annoyance to); but a much bigger sort of animal- 
cules ° whose bodies were roundish, so pestered one of 
these little animals, not only getting on her body, but also 
by clinging on to her horns, that in spite of all the struggles 
she made with her horns and body, she couldn’t shake it 
off; and I noticed afterwards that the little animal had 
lost one of her horns.* 
“ What seemed to me remarkable and wonderful, 
was that these little animals would oft-times let down 
their horns so far, that you would think, on seeing them 
through the microscope, that they were several fathoms 
long. 
At one time or another I let the draughtsman have a 
look at the horns as they were being stretched out, or 
anon pulled in; and with me he was forced to exclaim 
‘What wonders are these!” For as the creature pulled 
in its horns, they became perfectly round, and the closer 
they got to the head, the thicker they became, and when 
they were pulled right in, they formeda still bigger round 
blob. 
I charged the draughtsman to draw, as well as he was 
able to, a small part of a horn when so stuck out, which 
is here shown in Fig. 6, NOP. On this part are shown 
' Evidently the “common polyp-louse”’, Trichodina pediculus. 
2 The “large polyp-louse”, Kerona. The ciliates ectoparasitic on Hydra 
were again studied and described at a much later date by Rosel von 
Rosenhof, Trembley, Baker, and others. This is the earliest account 
of them. 
* “in the scuffle’ is added here by Chamberlayne—a_ picturesque 
addition, but not authorized by L.’s own words. 
* T have translated the remainder of L.’s remarks on Hydra because they 
are so entertaining : they contain no further observations on protozoa. But 
Hydra, rotifers, and protozoa were all “ animalcules ” for L., and he did not 
separate them zoologically ; so his views on one sort are illustrative of his 
notions about all. 
