630 Annals of the South African Museum. 



expected to behave differently during germination, and it seems 

 within the bounds of possibility that the early descriptions of 

 germination in F. aureus really apply not to oospores but to 

 parthenospores. 



The present investigation has not been decisive as regards the 

 number of zoospores formed, nor has it dealt with reduction division. 

 Further, except in one case, and that a doubtful one, no sign of 

 vestigial zoospores has been seen within the vesicle containing the 

 single large zoospore. Occasionally there have been seen zoospores 

 containing more than one (up to four) nuclei, and it is possible, though 

 not probable, that three of the nuclei resulting from reduction division 

 may degenerate without any corresponding division of the cytoplasm 

 occurring. 



To sum up, then, the present investigation leaves several very 

 important problems for future research : 



(1) Does reduction division take place as supposed during the 

 period of enlargement of the spore subsequent to escape from the 

 spiny epispore ? 



(2) Does reduction division always occur in the germination of the 

 apparent oospore, or only in certain cases ? 



(3) If the latter is true, are some of the resting spores really 

 parthenospores ? 



(4) When a single zoospore is formed, is it a result of reduction 

 division or not ? If not, then it is presumably formed from a 

 parthenospore. 



(5) If the single zoospore results from reduction division, do the 

 remaining three nuclei degenerate without corresponding division of 

 the cytoplasm, or are vestigial zoospores formed within the endospore ? 



A few details, notably the mode of formation of the endospore 

 protuberance, the actual escape of the zoospore, and the escape of 

 the Juvenile from its surrounding vesicle, in addition to the all- 

 important act of fertilisation, still remain to be observed. 



2. Form of the Colony resulting from Germination. No distinctive 

 Juvenile form has ever been recorded for Volvox, yet in both V. 

 Eousseletii and V. capensis the Juvenile is so remarkable that it might 

 easily be mistaken for a distinct species. Probably it is only in those 

 forms of Volvox where the number of cells is exceedingly large that 

 such a transitional form is produced, while in the other sections of 

 Volvox, all of which have comparatively few cells (1000 to 4000), 

 the difference between the first-formed colony and later generations 

 is so slight that it hardly constitutes a distinct form. In V. globator 



