Volvocina.~] THE INFUSORIA. 127 



1758, in the tenth edition of his Sy sterna Naturae. This 

 genus, as first described by him, comprehended the entire 

 race of Infusoria, excepting only eleven of the tribe Vor- 

 ticella, which were separated from them, under the 

 denomination of Hydra, the two species of V. globator 

 and V. chaos containing all the rest. In his twelfth 

 edition (1766) of the same work, he distributes the 

 Infusoria into four genera, viz., the Vorticella, Volvox, 

 Hydra, and Chaos. 



The Volvox is characterized by the members aggre- 

 gating under a transparent shell-like lorica, of the form of 

 a hollow globe, the creatures being distributed over the 

 internal surface of it. Each animalcule possesses the red 

 eye and a double filiform proboscis, which latter protrudes 

 beyond the surface of the lorica, so as to give it the 

 appearance (where great numbers of these creatures are 

 assembled to form the globe) of being covered with cilia. 

 Their different modes of increasing by self- division are 

 especially characteristic of the genus. 



Formerly the whole globular mass was regarded as a 

 single warty or ciliated animalcule, and the bursting of the 

 globe, whereby a few which had come to maturity and 

 previously left their positions in the lorica, were liberated, 

 was considered as the birth of the single animalcule. 

 This theory Ehrenberg clearly proves to have been 

 erroneous, and shews that a somewhat deeper research is 

 necessary in order to determine the organic relations of 

 the creature. The individual animalcules are the little 

 green wart-like bodies or specks which are to be seen on 

 the surface of the globe, and singly resemble Monads. 

 They have the same relation to their globe as the indi- 



