Of the Wheel Animal. 277 
pufhes its Head forwards, directing it this 
Way and that'Way with a great Deal of Agi¬ 
lity, and feemingiy in Search of Food. In 
the mean While, many minute Animalcules 
and other little Bodies are drawn along wdth 
a rapid Current of ¥/ater, fome whereof are 
taken in and fwallowed, and others rejected, 
though brought to the Opening of its Mouth, 
which appears exactly in the Middle, be¬ 
tween the two above defcribed Semi-circles. 
While the Sides of the Wheels are thus 
doubled as it were together, there is little or 
no Appearance of any circular Motion, the 
Fibrillce about their Edges feeming.to have 
only a quick Vibration : but mofc commonly, 
after two or three Minutes, this extraordi¬ 
nary Apparatus becomes protruded farther, 
the two Semi-circles pufh out, and open at 
the fame Time - 3 each of them immediately 
refembles a complete Circle or Wheel, feems 
to turn round very regularly, and its little 
FibriUce appear changed into Cogs or Teeth, 
in the Manner above mentioned. 
As the Animal is capable of thrufling thefe 
Parts out, or drawing them in, fomewhat 
in the Way that Snails do their Horns, the 
Figure of them is different in their ieveral 
Degrees of Extenfion and Contraction, or ac¬ 
cording to their Petition to the Eye of the 
Obferver, whereby they not only appear in 
all the various Forms before reprefented, but 
feem at certain Times as if the circular Rim 
T 3 of 
