436 Annals of the South African Museum. 



identical pool in which Mr. Rousselet originally found it, very satis- 

 factory further information concerning it might be obtained. Conse- 

 quently an attempt was made by Miss E. L. Stephens in 1927 to 

 locate the spot indicated by Rousselet in his paper to the Royal 

 Microscopical Society in 1906,* and as a result of her inquiries 

 she came to the conclusion that Rousselet had made his collection 

 at Old N'gamo, 5 miles north of the present N'gamo station and 

 23 miles north of Gwaai. She visited the vlei, which is an extensive 

 one several acres in area in the wet season, with the railway on 

 an embankment built across it, and collected Volvox. An accident 

 unfortunately happened to the material and all the Volvox perished 

 before it could be examined. In July 1930, however, Miss Stephens 

 and one of us were able to revisit the vlei and we found Volvox swarm- 

 ing in parts of it, chiefly in the deep part alongside the embankment. 

 It was particularly abundant in the partially shaded water in a culvert 

 under the line connecting the two parts of the vlei ; this part is prob- 

 ably the last to dry up, and it may have been here that Mr. Rousselet 

 collected. On this occasion the dominant form was F. aureus, but 

 another form, very like V. Rousseletii but still more like the form 

 found on the Cape Flats, was present as well, in all stages both sexual 

 and asexual. 



But subsequently we found another more detailed account by 

 Rousselet,f made several years later, in which he states explicitly 

 that he collected the Volvox at Gwaai station : ' the train stopped 

 for half an hour at this station by the side of a shallow pool formed 

 by the Gwaai River." Thus his two accounts are contradictory. It 

 has not yet been possible to revisit Gwaai, but we know that there 

 too, for part of the year at any rate, are pools close to the station. J 

 Probably no one can now prove which of Rousselet's two accounts is 

 the correct one. If the first account is correct, then Old N'gamo must 

 have been the spot where he collected, and it would appear that the 

 doubt expressed above was justified, for while the material found at 



* Journ. Roy. Micr. Soc., 1906, p. 393. Mr. Rousselet says that he had col- 

 lected it at " a station beyond Gwaai, where a stream forms a rather shallow pool 

 close to the station." Formerly the Victoria Falls train stopped at Gwaai, and also 

 23 miles farther north (to take in water) at what is now Old N'gamo. Gwaai at 

 present is an unimportant siding and Old N'gamo not even a halt, while a new 

 station has been made at N'gamo. 



t Rousselet, C. F., Journ. Quek. Micr. Club, vol. xii, ser. 2, 1913-1915. 



J In April 1925 one of us, unconsciously imitating Rousselet, jumped from 

 the train during an all too brief halt at Gwaai and secured several dips from 

 adjacent pools, but unfortunately without finding Volvox. It was the end of a 



