6o8 



M I C R O SCOPICAL E S SAY 3. 



XVI. VOR TIC ELLA. 



Vermis contra£tilis } nudus, ciliis rotatoriis. A worm capable 

 of contracting or extending itfelf, naked, with rotatory cilia. 



283. Vorticella Viridis. Fig. 31, Plate XXVI. 



Vorticella cylindracea, uniformis, viridis opaca. Cylindrical, 

 uniform, green, and opake. 



To the naked eye it appears as a fmall green point, through 

 the microfcope as an opake corpufcle, of a dark-green colour, 

 cylindrical, obtufe at both extremities, yet rather thicker in the 

 fore-part a ; very fimple, deftitute of limbs, not changing it's 

 figure. Notwithstanding it's fimplicity, the continual motion 

 into which it puts the water gives room to fufpecl that it is fur- 

 nifhed with an invifible rotatory inftrument, it moves fometimes 

 circularly, fometimes in a fijait line, a the fore-part, b the hind- 

 part, c fhort hairs. 



284. Vorticella Sphaeroida. 



Vorticella cylindrico-globofa, uniformis, opaca, A globous 

 cylinder, uniform and opake. 



To the naked eye it appears little more than a point fwimming 

 about in the water; but with the microfcope as a globular mafs, 

 of a dark-green colour ; they occafion a vehement motion in the 



adjacent 



