520 Annals of the South African Museum. 



FIO. 



D to F. Inversion nearly complete. D, median focus showing the two pairs of 

 equatorial gonidia projecting ; cilia just beginning to appear. E, same 

 colony, top focus showing the edges of the closing phialopore. The cells 

 round the edge show connecting protoplasmic strands ; in the background, 

 out of focus, the four equatorial gonidia, and on the left one of the posterior 

 gonidia, are just discernible. F, recently inverted colony at a slightly 

 later stage, the phialopore nearly closed and the gonidia sinking inwards to 

 their final position (669, 671, 660). 



A x 340. B, D to E x 520. C x 680. 



PLATE XXXIV. 

 Volvox Rousseletii G. S. West, forma griqunensis, f. nov. 



A. Group of asexual, male and female colonies fairly early in the sexual phase ; 



some males very large, larger than any females present. One asexual colony 

 with 11 embryos (575). 



B. Four colonies, one asexual, one very young female with developing oospheres, 



and two males, one young with numerous developing antheridia and a few 

 mature sperm globoids, the other mature (cf. Plate XXV, D, A, and B) (577). 



C. Group of " Juveniles," with one, two, or three daughter colonies and three free 



second-generation colonies ; below on the left a young Sphaerocystis colony 

 in the Eudorina stage (700). 



D. E. " Juveniles '' produced by germination of oospores. D, a young Juvenile 



with gonidia just beginning to divide and a young colony of the second 

 generation recently escaped from its Juvenile parent. E, an older Juvenile 

 with three developing embryos and an undivided gonidium. The large size 

 of the cells and the protoplasmic connections are distinctive (700, 703). 



A x!2. B, C x38. D x 78. E x 100. 



PLATE XXXV. 

 A to F, Volvox Rousseletii f . griquaensis. 



A, B. Male colonies : A, young ; B, mature (578, 579). 



C. Two mature sperm globoids in situ, seen in side and surface view respectively 



(574). 



D, E. Female colonies ; A, very young, oospheres still enlarging ; E, mature, 



oospores orange in colour (580, 581). 

 F. Group of nearly ripe oospores in situ (582). 



G, H, Kirchneriella africana sp. nov. 



Portions of two colonies showing cells of various shapes and sizes facing in all 

 directions, and some groups of young cells formed by division of a single 

 parent cell ; empty cell walls appear like two triangles standing on a common 

 base (680, 695). 



A, B, D, E x 60. C, F x 426. G x 383. H x 340. 



