158 NATURAL HISTORY 



is much longer than any of the preceding : it is shewn 

 at figures 212 and 213 : it is very common to observe 

 these in pairs, each branch having two bells. 



376. VoRTicELLA umhellaria. — Clustering Vorticella ; 

 first noticed by Roesil, from whom the drawing of one 

 of the globular bells, figure 225, is taken. Found in 

 stagnant water. 



377' VoRTTCELLA ovifera is found in clear water, and 

 was first described by Spallanzani : the buds are large, 

 and the main stem is sheathed, as shewn in figure 226 -, 

 in other respects it is similar to the V, anastatica, of 

 which it appears to me to be only a variety. 



378. VoRTicELLA fraxinina, — ^These are gregarious 

 animalcules, and differ from the V. digitalis only in being 

 destitute of a main stem. 



379. VoRTicELLA vaginata. — This polype is enclosed 

 in a transparent shell-like tube, as shewn at figure 227 • 

 the bell is fiirnished with rotatory cilia : in other respects 

 it has a strong resemblance to the Trichoda, figures 

 178 and 179. 



380. VoRTicELLA patellina. — This is a very broad po- 

 lype, with a taper stem, as shewn at figure 216. 



381. VoRTicELLA annularis, — The ringed Vorticella is 

 a large species, often found adhering to small fresh water 

 shells. The bell is rather conical ; the base of which, 

 when closed, appears to have two or three rings or bands, 

 which connect it with a stem that is generally twisted. 

 Figure 246 shews an open and a closed bell, both mag- 

 nified ; and figure 247, their real size. 



382. Vorticella globularia.—The ball Vorticella does 



