Volvox 



29 



cellular beings. In this genus the cells in place 

 of simply dividing, as in the Amoebae, into inde- 

 pendent organisms unite and form a colony 

 consisting, it may be, of as many as 1,200 cells; 

 each cell consists of a mass of nucleated proto- 

 plasm which is 

 united to its neigh- 

 bour by means of 

 processes formed 

 from their body- 

 substance ; from 

 each cell two fla- 

 gella project by 

 means of which the 

 colony is paddled 

 through the water. 



(Fig. i.) 



The cells of a 

 Volvox multiply by 

 a process of division, but after a time they ap- 

 pear to become exhausted ; or at any rate, some 

 of the cells fuse to form one or more large or 

 female organ cells ; at the same time other cells 

 of the colony develop smaller flagellated male 

 cells, which escape from the parent colony and 



FIG. i. Volvox, showing the small 

 ciliated somatic cells and eight large 

 germ cells. (Drawn from life by 

 J. H. Emerton. See E. B. Wilson, 

 The Cell in Development and In- 

 heritance, p. 123.) 



