638 Annals of the South African Museum. 



Note. Volvox from Grahamstown. 



In the paper entitled " Observations on the Genus Volvox in 

 Africa (Rich and Pocock, 1933, p. 460) a form of Volvox is recorded 

 from Grahamstown. The material was nearly all asexual and in 

 the absence of mature sexual colonies was provisionally included 

 under Volvox Rousseletii West. 



Quite recently a further supply has been sent by Miss Britten 

 (Britten, 4170, 4173, 12th-14th March 1933). This includes a small 

 number of sexual colonies in various stages of development. 



The oospores are still green even in the oldest colonies, but are 

 quite clearly of the V. caj)ensis type, the spines being broader and 

 shorter than in V. Rousseletii. 



Male reproductive bodies are unfortunately scarce, but there are no 

 separate male colonies and the few mature sperm-globoids seen are 

 all in young monoecious colonies associated with numerous very 

 young oospheres, i.e. this Volvox is a monoecious species with 

 oospores similar to those of the Cape Flats form. 



It must therefore be diagnosed as Volvox capensis and not as 

 V. Rousseletii as previously thought. 



Its occurrence is curious- so far, in the Grahamstown district it 

 has been found in one locality only, a rocky pool in quartzite forma- 

 tion at the foot of a small clifi in the woods near the Mountain Drive. 

 It appears to be somewhat capricious in its periodic appearances 

 and when seen by the writer has always been somewhat unhealthy 

 looking, although fairly large. The first collection was rather badly 

 attacked by Rotifers, the second by an amoeboid parasite. This 

 may perhaps be connected with the fact that the pool in which it 

 occurs is among trees and gets little direct sunlight. 



Dimensions. 



Asexual colonies . . . ? - 969 /x x ? -1141 ^ 



Daughter colonies . . ? - 322 p x ? - 345 p, up to 



8 per coenobium 



Sexual colonies . . . ? -1012 ^ x ? -1098 ^ 

 Oospores (immature) with 



spines .... 48- 50 [i 

 Oospores (immature) without 



spines . . . 35- 38 /x 



Sperm globoid . . . 37- 40 JJL 



