546 ANIMALS KILLED iV) 
the vibrating points or fibres of infufioh animal- 
cula, forming two great vortices which convey the 
animal’s food to it. A wheeler is exhibited, with 
the trunks extended, and the fibrils whofe mo- 
tion refembles that of two wheels,,and forms two 
vortices, fig. 5, plate 3. 
When I fay, the wheels of my animalcula are 
fuch only in appearance, I do not mean that this 
will extend as a general rule to all. The optical 
illufion indeed has been correéted by fome na- 
turalifts, particularly M. Trembley and Bonnet ; 
but it is certain, that the opinion of others 
is different. Leeuwenhoeck, that deep and 
acute obferver of the moft minute objects, ac- 
tually calls them wheels, which revolve like thofe 
conftructed by mechanics: Baker, who is not 
inferior to him in accuracy of obfervation, and 
has ftudied the wheels moft attentively to difcov- 
er whether they are truly fuch or only vibrating 
fibrillz, is more inclined to believe them wheels. 
What thefe two able naturalifts have obferved 
may very well coincide with my remarks, for 
their wheel animals have been {pecifically differs’ 
ent from mine. A fingular aperture for a mouth 
fituated between the wheels, a fort of ring be- 
neath it, a number of ferpentine veflels in the 
head, the periftaltic motion of the inteftines, the 
irregular agitation of a tranfparent fluid in every 
part of the body, a particular undulation of that 
fluid 
