VOLVOX 



121 



individual of normal size. In this case a small active cell 

 (like a spermatozoon) fuses intimately with a larger passive 

 cell, which may be compared to an ovum. 



Sixth Type of Protozoa — Volvox 



Volvox is a type of flagellate Infusorians, especially of 

 those with flagella of equal size. 



Volvox is found, not very commonly, in fresh-water pools, 



Fig. 54. — Volvox globator. — After Klein and Janet. 



I. and v. Biflagellate individuals. II. Ripe ovum. III. A ball 

 of sperms. IV. A daughter colony developing. 



and is usually classed by botanists^ as a green Alga. It 

 consists of numerous biflagellate individuals, connected by 

 fine protoplasmic bridges, and embedded in a gelatinous 

 matrix, from which their flagella project, the whole forming 

 a hollow, spherical, actively motile colony. In V. globator 

 the average number of individuals is about 10,000 ; in 

 V. aureus or minor, 500-1000. The individual cells are 

 stellate or amoeboid in V. globator^ more spherical in V. 



