t 
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the female, in which (it being quite tranfparent) 
the ova, or fpawn, are very vifible, and may be 
feen, from time to time, to change their places, and 
to have a kind of circulation. 
C is a view of the female, placed on its back, in 
order to fhew the pofition of the fins, and their ap- 
pearance when one looks down upon the miedf ; and 
D is the male, placed with his back uppermoft, in the 
pofture in which hefometimes lies dill at the bottom of 
the water. Laftly, b is the tail magnified in a micro- 
fcope, fhowing the hairs which grow on both fides 
out of it ; but as the animalcule did not lie ftill long 
enough in the water, I could not view it with a 
glafs fo exactly as I wifhed to do, and, therefore, 
am not fure of the accuracy of the drawing of this 
part ; all the other parts I have drawn as carefully as 
I was able, and they are about the natural fize. 
In thefe infers, befides their form, feveral parti- 
culars are very remarkable, i. Their bodies are in- 
tirely tranfparent, and moftly of a yellowifh hue, 
except towards the tail, and part of the ovarium, 
where the color is reddifh ; and, through a long vef- 
fel, which reaches almoft the whole way, from the 
head to the tail, fomewhat of a circulation, by fits and 
Harts, is very vifible, even to the naked eye. 2. In 
the ovarium of the female, the ova (which are of a 
mixed color in different parts, fome brown, fome 
yellow, and fome red) are alfo in a conftant circular 
motion round the bag (or at leaft, by a deception of 
fight, they appear to be fo). 3. They fwim con- 
ftantly on their backs, keeping themfelves fufpended 
by the vibrations of their numerous fins, and 
moving forwards, by giving a fudden fpring with 
Vol LVII. L their 
