15G 



NATURAL HISTORY 



bag : when extended, the base is rather pointed. Found 

 attached to the Monoculus minutus, (Microscopic Cabi- 

 net, pag-e 88.) 



369. VoRTicELLA socialis. — These animalcules are 

 found in societies, and appear to be the V. crategarioy 

 with separate stems. The cluster, when expanded, is 

 sometimes nearly half an inch in diameter. 



370. VoRTicELLApj/nybra^w. — This elegant species is 

 larger than the V. convallaria, or common bell polype, 

 with which it has been confounded. Under a good mi- 

 croscope, the stem will be observed enclosed in a sheath, 

 like the genus Vaginicola, Book III. : it contracts in 

 a zig-zag line (see figure 211), and is often sur- 

 rounded by small protuberances like buds ; these are the 

 ova. Miiller calls them knobs or scales. The bell of the 

 animalcule is contractile, as shewn at the larger figure. 

 To discover the existence of the stem within the sheath, 

 it requires a magnifying power of 300 times : this stem 

 has recently been examined by Mr. Varley, who consi- 

 dered it to be the muscular fibre. (Trans. Soc. Arts, v. 48.) 



371. Y oKTic^L.i.\f asciculata, (Carchesium,!^.) — This 

 belongs to the same genus as the preceding : the 

 stem is sheathed, and the edge of the bell deflected : they 

 are found in clusters, floating about on the surface of 

 stagnant water ; size, 1 -400th of an inch. 



372. VoRTicELLA nehuUfera, {Carchesium, E.) — The 

 body is pear-shaped; the stem and the edges are de- 

 flected ; but when it contracts the stem, the cilia are 

 withdrawn, and the bell assumes an egg-shape. 



