Volvocina.'] infusorial animalcules. 103 



is the type of the family Volrochia, was instituted by Linneiis, 

 and in-omulgatcd to the world in 1758, in the tenth edition of his 

 Systema Naturae. This genus, as fii-st described by him, compre- 

 hended the entire race of Infiisona, excepting only eleven of the 

 tiibe VorticelJa, which were separated from them, imdcr the deno- 

 mination of Hydra, the two species V. glohator and V. chaos con- 

 taining all the rest. In his twelfth edition (1766) of the same work, 

 he distributes the Infusoria into four genera, \'iz., Vorticella, Volvox, 

 Hydra, and Chaos. 



Volvox is characterized by the members aggregating under a trans- 

 parent shell-like lorica, of the form of a hollow globe, the creatures 

 being distributed over the internal siu'face 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 ap- 

 pearance (where gi'eat numbers of these creatures are assembled 

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

 inner globes, 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 shows that a somewhat deeper research 

 is necessary in order to determine the organic relations of the crea- 

 ture. 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 individuals of Gonium pedorale hold to their tabular 

 clusters. Each sphere or globe is a hollow cluster, if we may so 

 term it, of many hundreds, or even thousands of these living occu- 

 pants, and often contain vtithin it other hoUow spheres, similar in 

 nature to itself. 



The individuals are protected by a gelatinous lorica or mantle 

 (Jacerna), of the form of a bell, which ihej are enabled to leave, 

 when full grown. They are connected with their neighbours by 

 from three to six filiform cords or tubes. The mouth is situated at 



