Volvox in South Africa. 637 



llth August. Juvenile 120x133 p, gonidia dividing; in structure 

 and appearance exactly similar to those found on the Cape 

 Flats. 



13^/z August. Mature Juvenile with daughter about to invert. 



15th August, 6.30 p.m. Germ colony in 4-celled stage found, 

 moving actively. Watched through completion of cell-division 

 and inversion until 3.17 a.m., when the colony was beginning 

 to rotate within the vesicle, after which the colony was lost. 

 This developing colony continued motile until after the fifth 

 cell-division ; before the 64-celled stage the zoospore cilia ceased 

 to function (figs. 9, G-L, and 10, A-I ; Plate XLVII, A-F). 



23th August. Many Juveniles, up to 199 x 208 jit, and second genera- 

 tion colonies up to 667 x 689 p, with from 4 to 10 daughters. 



Culture III. 



llth February. Oospore material from stock jar put on slides and 



left to dry ; put on one side for later use. 

 24th July. Slides placed in dish in water, and the whole placed as in 



Culture I. 

 1th August. Strained vlei water with a small quantity of Uspenski's 



culture solution added. 

 21st August. Slide lifted out of dish and examined. (1) Many 



oospores in various stages of germination. (2) Zoospore escaping 



from mesospore into protruding endospore (Plate XL VI, G). 



(3) Zoospores moving about on slide (Plate XLVI, I, J). (4) 



Zoospores in various stages of division 2-, 4-, 8-, 16-celled, etc. 

 22nd August. More of the above, and in addition a mature Juvenile 



with nearly mature daughter. 

 23rd August, 12.30 p.m. Two-celled stage found and watched through 



stages of division up to 128-celled stage at 8 p.m. Movement 



here ceased after the 4-celled stage, before the third division. 

 Many Juveniles of all sizes, some just changing colour green 



with a few globules of the red pigment. 



Colonies of the second generation up to 244 x 267 JJL with from 



5 to 9 gonidia mostly in early stages of division. 

 31st August. Zoospores in various stages of cell-division. 



A 7 . B. Whereas most second generation colonies were obtained 

 from Culture II, the method used in Culture III, i.e. letting oospore 

 material dry on a slide and later ernersing it in water or other culture 

 medium, is undoubtedly far the best for observation of the zoospore 

 and its development. Of other cultures, those not in the sun did 

 not go beyond the first stage in germination a few spores escaped 

 from the spiny exospore, but most showed no sign of germination. 

 If the culture solution (Uspenski's) was used full strength, the 

 Juvenile colonies which developed showed abnormalities, the cells 

 tending to separate from one another. 



^^o \ P M i 







