OF ANIMALCULES. 145 



First Division.— POLYGASTRICA. 



342. VoRTicELLA vividis. — The green Vorticella is 

 found in clear water, and on close inspection can be 

 perceived by unassisted vision : it is long and nearly 

 cylindrical, but rather larger at the anterior, which is 

 furnished with cilia ; these produce a vortex in the water : 

 the end is spherical ; it does not contract or alter its 

 shape, and in swimming it often rotates on its longer axis. 



343. Y oKTic^LL A splicer oidea. — The globular Vorticella 

 is, like the preceding one, of a dark opaque green colour ; 

 it is somewhat egg-shaped, and the anterior has a circle 

 of rotatory cilia. 



344. Vorticella ciiicta {Peridimmn cincta, E.) — The 

 girdle Vorticella, sketched at figs. 23/ and 238, is of an 

 opaque green colour, nearly globular, and furnished with 

 transverse bands of cilia : when about to divide, it elon- 

 gates in one direction, and the middle becomes transparent. 



345. Vorticella lunifera. The moon-shaped Vorti- 

 cella in form resembles the moon at her first quarter : 

 the mouth, situated near the middle of the convex edge, 

 is furnished with cilia ; the two horns are rounded, and 

 form the sides of the animalcule ; at the centre of the con- 

 cave side (which is the posterior part of the animalcule) 

 is a small projection. Found in sea- water. 



346. Vorticella bursata. — 2'he purse-shaped Vorti- 

 cella, shewn, magnified, at figure 207, has a short pel 

 lucid neck, the edge of which is surrounded with cilia : 

 this transparent envelope terminates the anterior extre- 

 mity of the body in a conical point, as seen in the draw- 



