284 Of the Wheel Animal . 
Though this Infedfc fwims very Jfwiftly, and 
feemingly with great Eafe, neither Legs nor 
Fins can be perceived to affift it in fo doing, 
u'nlefs thofe'juft now mentioned about the 
Tali, and the Horn under the Breaft, may be 
imagined fuch. Wherefore fince the Wheels 
in its Head are always fet to work very 
brifkly whenever it begins- to fwim, one 
may reafonably prefume they are the 1 nftru¬ 
men ts by which it performs this Office. 
And, indeed, looking at the Manner of its 
fwimming through a Hand Magnifier, when 
it is at large in a Phial of Water, will confirm 
this Opinion greatly ; for there one fhall 
often difcern it rifing in a perpendicular Di¬ 
rection, and by the Rotation of its Wheels 
climbing as it were upwards and mounting 
through the Water ; but finking down a- 
gain inftantly upon the ceafing of their 
Motion. 
As I call thefe Parts Wheels , I alfo term 
the Motion of them a Rotation , becaufe it 
has exactly the Appearance of being fuch. 
But fome Gentlemen have imagined there 
may be a Deception in the Cafe, and that 
-they do not really turn round, though 
indeed they feem to do fo. The Doubt of 
thefe Gentlemen arifes from the Difficulty 
they find, in conceiving how, or in what 
Manner, a Wheel, or any other Form, as 
Part of a living Animal, can poffibly turn 
upon an Axis, fuppofed to be another Part 
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