Microscopical Essays. 



439 



which are reprefented at Fig. 29, Plate XXII. There was no 

 main flem, but all the pedicles were joined in one center, round 

 which the animals extended themfelves as fo many radii, forming 

 a very pleafing figure. 



The mouths of thefe animalcula are not ciliated, but they are 

 furnilhed with a round aperculum, or cover, connected by a long 

 ligament, or mufcle, which extends downwards through the 

 body, and is affixed within fide of it, near the tail. This liga- 

 ment may be contracted or dilated, fo that the cover may be 

 removed to fome diftance from the mouth ; in this fituation feveral 

 fhort hairs may be found to radiate from it ; thefe have a vibra- 

 tory motion, by which they excite a current of water, moil 

 probably to draw in the proper nourifhment, after which they 

 fhut or pull down the cover, which they again extend at plea- 

 fure ; when the cover is pulled clofe down, the mouth contract 

 and no hairs are to be feen* 



Fig. 29 reprefents the vorticella opercularia, f the operculum 

 removed at fome diftance from the mouth, at t, it is nearly clofe 

 at r, the mouth contracted, the cover drawn in, and no hairs to 

 be feen ; u a part of the ftalk, from which fome of the animal- 

 cula are feparated. 



Vorticella Umbellaria. 



Vorticella compofita, floribus ciliatis globofis muticis, ftirpe 

 umbellata, Fig. 30, Plate XXII. Compound, with ciliated 

 p-lobous naked florets, and an umbellated ftem* 



VortI- 



