LECTURE XII. 223 



scribed by a German author of the name of Eichorn, 

 and afterwards more fully by M tiller. 



The genus called Volvox also presents one of 

 the largest and most curious of Animalcules, as 

 well as one of the most beautiful, the chief spe- 

 cies, or Volvox Globator, often equalling the size 

 of a pin's head. In the advanced state of spring, 

 and again in autumn, it appears in immense num- 

 bers in the clearer kind of stagnant waters. Its 

 general colour is green ; but it sometimes is of a 

 pale orange-colour. Its motions are irregular, in 

 all directions, and at the same time rolling or spin- 

 ning as if on an axis. When microscopically ex- 

 amined it presents one of the most curious pheno- 

 mena in natural history, being always pregnant with 

 several smaller animals of its own kind, and these 

 with others still smaller : the whole external surface 

 is covered with very numerous small tubercles; 

 which some have supposed to act as a kind of fins, 

 while others have supposed them to be the valves 

 of so many orifices which the creature can either 

 open or close at pleasure, in order to manage its 

 various motions. When groupes of these beauti- 

 ful animalcules are viewed by the solar Microscope, 

 they strongly recal to the recollection of the spec- 



