OF ANIMALCULES. 149 



It is found near the surface of the water, among confcrvfe, 

 and is about I -50th of an inch in length and breadth. 

 The head has a circle of cilia, the sides of which, by pre- 

 senting to the view a greater number in the same space 

 than the middle, have been mistaken for horns. 



351. VoRTicELLA a/6ma. — This animalcule resembles 

 a small steutoria, the end terminating in a point. 



352. VoRTicELLA cucullus is about l-20th of an inch 

 Iqng, of a dull red colour, conical, with the circle of cilia 

 apparently within its lip. Found in sea- water. 



353. VoRTicELLA ocvcata — V. valga. — These animal- 

 cules, described by Miiller as distinct species, appear to 

 belong to the polymorpJia, undergoing division. 



354. VoRTicELLA coiivallaria — V. bellis — V. sem'ila. 

 The bell-shaped Vorticella or Polype is an entertaining 

 and well-known animalcule ; it is usually found attached 

 to any extraneous body, as the leaves of duck- weed, small 

 aquatic shells, clusters of ova, and the larvae of insects ; 

 an example of the latter is shewn in the Microscopic 

 Illustrations, figure 30, where it may be considered as a 

 parasite, or rather an epiphytes. As they are, when fully 

 developed, attached mostly to some stationary object, 

 they afford many facilities to the Microscopist for his 

 observation ; they form a good object also for ascertaining 

 the defining power of his instrument, and his expertness 

 in its management, as much of the effect will depend on 

 the manner in which he directs the illumination. If this 

 be not attended to, and the instrument have not sufficient 

 power and penetration, it will only exhibit two cilia 



