Volvox in South Africa. 627 



from the Juvenile parent quite normally (Plate XLIX, A, C, D), 

 but are always fewer and larger celled, and on the average consider- 

 ably smaller than typical adults (Plate XLIX, E). They undoubtedly 

 constitute a transitional stage, and are fairly easily distinguished from 

 the true adult which appears in the next generation, i.e. in their grown- 

 up daughters. In the oospore cultures colonies of the second genera- 

 tion containing from four up to ten daughter colonies were obtained ; 

 in the majority of cases, however, both from cultures (Plate XLIX, E) 

 and in the field the number of gonidia which develop in the second 

 generation is comparatively small in the photograph, in addition to 

 the four developing daughters, two abortive gonidia can be seen. 

 This photograph also shows very well the coarse appearance of the 

 cell network due to the large size of the cells ; the difference in 

 texture between the second and subsequent generations is indicated 

 in the group from the Flats (Plate XLIX, A) ; on examination of 

 the colonies included in it, it can be seen that the lower one on the 

 right, in proportion to its size, is composed of fewer and considerably 

 larger cells than the large upper colony on the left. While the cells 

 in the anterior part of the colony are more widely spaced than the pos- 

 terior (Plate XLIX, F, G), the difference is on the whole less marked 

 than in typical adult colonies, the cells in both regions being markedly 

 larger than those in corresponding regions of the latter. These 

 photographs should be compared with the similar ones from a normal 

 colony of V ' . Rousseletii already figured (Plate XIV, B and C, D and 

 E) ; the colony from which they were taken was rather younger than 

 that shown in the adjacent photograph. 



So far as has been observed, the colonies of the second generation 

 are invariably asexual ; sexual cells are not differentiated until some 

 generations later. 



With the second-generation colonies the life-cycle is complete. 



Previous Accounts of Germination in Volvox. 



Accounts of germination of the oospore in Volvox founded on 

 actual observations are meagre in the extreme, and such as there are 

 refer exclusively to V. aureiis. 



The only reference found to germination in V. globator is con- 

 tained in a brief note describing a " growing slide " devised by the 

 Rev. A. Pagan (1887, p. 81), where it is stated that he observed "the 

 growth of spores of Volvox globator after they had been confined to 

 the slide for six weeks, the actual process of germination taking 



