i 1^9 ) 
cefTary, as well with regard to the different Motions 
of thefe two Parts, as to this Protuberance, which fe- 
parates them at their Beginning. This little Protube- 
rance, when it is in its greateft Extenfion that the 
Animal can give it, is of the fame Form with a little 
fpherical Air-Pump, and has all the fame Properties, as 
I fhall explain by and by. Its Situation is under the 
Body, and its Diameter is fuch as appears in the Fi- 
gure. I know not to what I can compare this Part 
better than to the Cup of an Acorn, with the Mouth 
a little contraded. The Head E, which makes the 
fmalleftEnd of this Worm, reprefentsno Part worthy 
of Obfervation, except a hollow Body underneath, of 
a conical, or almoft hemifpherical Figure, which 
feems to ferve it for a Mouth to fuck, as well as to 
fallen itfelf on. the various Bodies which come in its 
Way, after the manner of the other Leaches. 
The Belly B is of a dark Colour, becaufe feveral 
Bowels, which are contained in it, are filled with a 
thick, black Liquor, which makes it look as if the 
Skin was of that Colour. The fore Part C E is vari- 
oully ftiaped, according to its different Motions j fome- 
times it prolongs itfelf, and then it becomes (lender, 
the Diminution being made by Degrees up to the Head ; 
and fometimes it contrads- itfelf, and then the Thick- 
nefs encrealing, it becomes all of an equal Bignefs. 
The hinder Part CB does not change its Figure, be- 
caufe it moves but (lowly, and very feldom. The 
Motion of the fore Part is of three Sorts ; Prolongati- 
on, ContraQ:ion, and the making itfelf round on all 
Sides. The Protuberance alfo is endued with two 
Motions, Extenfion and Undulation, which is made 
G g g from 
