ALG/E, 129 



the common form of zoospore found in so many of 

 the algas, but, in this case, fixed at the periphery of 

 a revolving matrix in a combined family. By the 

 movement of the whole series of pairs of hairs, or 

 cilia, with which the gonidia are furnished, the little 

 spheres are kept in motion. By means of accurate 

 adjustment it will be observed that the gonidia are 

 connected with each other, telegraphically, by means 

 of two or three very delicate filaments, like the finest 

 of spider's web, so delicate that they can only be 

 distinguished with difficulty. 



! A certain number of these green points, or gonidia, 

 are privileged to produce a group of young individual 

 globes within the parent sphere, usually from four 

 to nine. Sometimes a daughter volvox, whilst still 

 enclosed within the parent sphere, will have in its 

 interior distinct evidence of the commencement of 

 its own daughter spheres. The process of develop- 

 ment of the selected gonidia into young plants is as 

 follows : The gonidium enlarges, and becomes flat- 

 tened and discoid, pressed to the inner surface of the 

 hyaline sphere, surrounded by eight ordinary zoo- 

 spores. Gradually the disc becomes oval with a 

 constriction across the centre. It then divides in 

 the opposite direction, so that it consists of four 

 segments. After this it protrudes more into the 

 inner cavity, and differentiation proceeds rapidly, 

 whilst a proper external membrane is developed. 

 Finally a green sphere, containing a vast number of 

 closely packed green granules, enclosed within a 

 proper envelope, is evolved. As this sphere enlarges 

 the granules separate from each other, leaving clear 



K 



