animalcular tribe, the higheft degree of contraCfile 
power; in confequence of which it occafionally appears 
in all the various Hates of elongation and contraction 
reprefented in the plate ; and not unfrequently reduces 
itfelf to a globular form. Its motions are rather flow 
than fvvift, and when fwimming at full length it gene¬ 
rally appears tranfparent at both extremities, while the 
body feems filled with a congeries of globules or grains 
of a green or reddifli colour, and not ill refem- 
bling the fpawn of filh. The head or fore-part is ob- 
tufe, but the tail or extremity is acute, and fometimes 
exhibits a flight appearance of bifurcation at the tip; 
but this is a particular which in general is fcarce to be 
perceived. The difference in colour between thefe 
animalcules feems hardly fufficient to juftify our regard¬ 
ing them as fpecifically diftinCt; fince both the green 
and the red fort are fo perfectly alike in other refpeCts 
that no difference can be perceived between them. 
The green fort may be very frequently obferved in 
molt ftagnant waters in the months of May and June, 
and fometimes much fooner, appearing commonly on. 
the furface in the evening and early in the morning, 
and retiring towards the middle of the day to' the bot¬ 
tom. The red variety is far lefs common, and the 
appearance which it fometimes exhibits is fuch as to 
alarm a fuperftitious mind with the idea of the water 
being tinged with blood: a panic of which numerous 
inftances have been adduced by authors; and which is 
the more excufeable in thofe who are ignorant of the 
caufe, as the animalcules are fo extremely minute as 
to be utterly imperceptible, (except to an uncommonly 
(harp 
