CIRCULAR VORTICELLA. 



Generic Character. 



Body contradlile : in fome fpecies naked j in others 



included in a fhell. 

 Cilia or rotatory fibrils furrounding the head or 



upper part. 



Specific Character, 



VORTICELLA with circular pellucid fhell and 

 double rotatory organ. 



This moft curious animalcule, which the plate 

 reprefents very highly magnified, may be confidered 

 as one of the rarer fpecies of Vorticella. It is found 

 in ftagnant waters in the month of may. The upper 

 figure fhews its appearance when the rotatory organs 

 and tail are extended ; the lower as it appears when 

 thefe parts are contradled within the circumference 

 of the circular tranfparent ^hell. The ftrong and 

 regular pulfation of the triple veficle in the middle, 

 or heart, (if it really be fuch,) is Angularly confpi- 

 cuous in this animalcule. 



