i: like the trelle string of a violin : their bocly Is formed 

 of the succession of a great number of little rings, which 

 decrease gradually as they approach ihe extremities. 

 They are very soft : their head, which terminates in a 

 blunt point, is susceptible of various motions ; it con- 

 tracts, dilates, lengthens, and shortens itself, at the plea- 

 sure of the insect. The mouth is furnished with a 

 muscle that directs the functions of it, and whose exer- 

 cise is pretty perceivable : tiie anus, which is placed at 

 the opposite extremity, is a little oblong aperture, bor- 

 dered v, ith an analogous muscle. The whole skia is so 

 transparent, as to admit of its being inspected within, 

 and we may congratulate ourselves on this circumstance, 

 since it affords us a great spectacle. The polypus ex- 

 hibits nothing that has the appearance of the viscera : 

 all its substance seems to be composed of a mass of 

 small similar seeds. Our fiddle-strings are minute 

 beings, quite differently organized ; and the apparatus of 

 the viscera, which the microscope discovers to us, seems 

 to advance them far above the polypus. A long vessel 

 : m>es -winding from the head to the tail, is what 

 .r-kes the eye of the observer: by its regular 

 alternate motions, he will soon know it to be^tlie heart, 

 or grand artery. The liquor that, circulates in these 

 winding passages is limpid : it is perceived, from the 

 pulsations it excites in every part of the artery, coin- 

 prized betwixt two of the rings. One would be apt to 

 imagine each of these portions to be a real heart, and 

 that every artery was a chain of little hearts, placed end 

 to end, and that forced the blood from one part to ano- 

 ther: it is seen to run with an uniform motion through 

 all these little hearts, and rises in this manner, as by so 

 many Madders from the tail to the head, near which it 

 finally disappears. In different parts of the artery are 

 discovered delicate ramifications of vessels, which may 

 be taken for veins, there being perceived no pulsation in 

 them : beneath, and along the artery, there is a canal, 

 whose diameter varies at different points of its extent. 

 It is the intestinal duct which comprehends the cesopha- 

 H 2 



