THE 
CHANGEABLE CERCARIA. 
Generic Character. 
Worm unobfervable by the naked eye, fomewhat 
pellucid, tailed. 
Specific Character. 
GREEN CERCARIA, (fometimes red,) with 
cylindric mutable body, and flightly bifid 
pointed tail. 
/ 
The animalcule of which microfcopical figures, very 
highly magnified, are reprefented on the annexed 
plate, is amongfl: thofe legions of animated beings 
which, in the warmer months, contribute to people 
the generality of ftagnant waters; fometimes covering 
the whole furface with a continued flieet of a red or 
green colour, and fometimes diffufing a ftrong tinge of 
thofe colours throughout the whole mafs or body of the 
water. The general fhape of this animalcule is not 
much unlike that of a flug, but its motions are more 
analogous to thofe of a leech. In its pollutes it is 
infinitely variable, poffeffing, like many others of the 
animalcular 
