IV. AND REVIVED, 139 
This is what I have obferved in my wheel ani- 
mals, and what fome of my friends have obferved 
along with me. I did not fee the three organs 
till after twenty-one days examination. Let the 
reader figure a {nail proceeding from its fhell ; it 
extends itfelf, and puts out the head and horns ; 
then retiring within its habitation, it is contrac- 
ted and conceals them within the body. In this 
manner he will fenfibly conceive the motions of 
the two trunks and wheels of our animalcula. 
Thofe then examined, and afterwards feen, did 
not always difplay both the trunks and wheels at 
the fame moment, but, like fnails, fometimes 
concealed the one and fometimes the other, which 
happened whenever they contracted themfelves ; 
and when remaining leng extended, the trunks 
_ and wheels were kept out a long time alfo. The 
wheels receive this appellation in a very improper 
 fenfe, and by means of a fort of latitude or ac- 
commodation.—In the traét on infufion animal- 
cula, I have treated at length of the minute; long, 
and flender fibrils proceeding from the edge of 
the mouth of many of thefe beings: I have faid 
they were in continual vibration ; that they pro- 
duced a certain vortex in the infufions, which 
carnied.the corpufcula feeding the animalcule te 
its mouth. ‘The wheels of wheel animals are on- 
— ly two circular lines of fimilar fibrille confiantly 
in motion: they produce the fame effect with 
f the 
