626 Annals of the South African Museum. 



curves, this structure being more marked than in any adult form. 

 Among the vegetative cells are found a varying number of repro- 

 ductive cells, gonidia, distinguished by their greater size, richer cell 

 contents with several pyrenoids, and greater number of connecting 

 strands (Plate XLIX, B). 



This description of the Juvenile form, as of the second generation 

 which follows, holds equally for V. Rousseletii and F. capensis. 

 In the latter, however, no stages in germination between the first 

 (escape of spore from the epispore) and free-swimming Juveniles 

 have as yet been seen. 



In the collections of Juveniles from the Cape Flats (Plates XL VIII, 

 E, F; XLIX, A) there has been remarkable uniformity of shape, 

 size, and number of component cells. The same holds for the rich 

 collection of Juveniles of V. Rousseletii from Kimberley. In the cul- 

 tures of F. Rousseletii oospores from the Rietfontein material, how- 

 ever, the Juveniles showed much more variation in the form and size of 

 the young colonies, and also in the number of component cells some 

 with as few as 60 cells and others with as many as 375 occurred, 

 although the majority had in the neighbourhood of 240. This varia- 

 bility is probably attributable to the artificial conditions of the cul- 

 tures. It is well illustrated by the series of photographs of Juveniles 

 from the oospore cultures (Plates XLVII, H-L; XL VIII, A-D). 



Development of the Second Generation. 



At a very early stage in the life of the Juvenile, before it has escaped 

 from the vesicle, some larger cells can be distinguished in the posterior 

 half (cf. Henneguy, 1879, p. 94, in the case of V. aureus). These 

 are the gonidia, probably usually four in number, although as many as 

 five developing daughters have been seen. Usually of these only one 

 or two (Plate XL VIII, D), more rarely three (Plate XLVIII, A, B), 

 develop. In the first collection of Juveniles from Keurboom Road 

 one was the usual number, two the exception. Later in the year, in 

 the very vigorous Dabchick Vlei collection, more Juveniles contained 

 two than one, while in the Kimberley material nearly 25 per cent, 

 contained three young daughters, while in one Juvenile as many as five 

 were seen. In the latter material, too, the Juveniles were unusually 

 large- several about 322 x 345 JJL with rotating daughter colonies up 

 to 194 x 215 ju were seen, while one of 322 x 366 p had a single mature 

 daughter of 215 x 240 p. 



These daughter colonies of the second generation develop and escape 



