Volvox and Associated Algae from Kimberley. 509 



PART III. FIELD OBSERVATIONS AND RECORDS. 



Pool I. The pool where Volvox was first found lies in an excava- 

 tion roughly 40 yards in diameter and about 3| feet deep in the 

 deepest part. It was made some eight years ago by the removal of 

 red clay for building purposes, and the bottom and sides are com- 

 posed of this red earth. Any water which lodges in it is very muddy 

 and of a reddish colour. It lies about a mile to the S.E. of 

 Kimberley, just off the Samaria Road and close to the Bultfontein 

 Floors. 



Volvox was first collected here in November and again early in 

 December 1931. The pool dried up about the middle of December, 

 but was filled again by a thunderstorm during the afternoon of 

 Saturday, 23rd January, and remained in existence for about four 

 weeks, the last collection being made on 18th February. By 24th 

 February it was completely dry. 



The third phase was started by a thunderstorm during the night 

 of Saturday, 27th February, and this time the pool had a rather longer 

 existence, another storm on 19th March partially refilling it before it 

 had quite dried, so that it continued some days longer ; but it was 

 dry again by 2nd April, and with that date the observations on this 

 pool finish. Volvox disappeared from it about the 19th of March, 

 and did not reappear. 



Pool II. No other Volvox pools were found until after the last rains, 

 when Volvox was collected in two more quarry pools. The second 

 one lies about 4 miles S.W. of the town. The sides and bottom are 

 of broken stone and the water clear. 



The phytoplankton consisted entirely of asexual material of Volvox 

 Eoiisseletii, with a very small proportion of Volvox africanus mixed 

 with it. Streptocephalids, abundant in all the pools, were particularly 

 so here. 



Pool III. The third pool is of yet a third type, though it also 

 is in a quarry. This quarry, however, is in limestone tufa which 

 forms the sides and bottom of the excavation ; the latter is covered 

 with mud and the water is very muddy. 



The pool lies about H miles N.E. of Kimberley ; it was fast drying 

 up when Volvox was first found in it and was only visited twice. 

 The Volvox was very scarce, and consisted entirely of asexual colonies, 

 mostly immature but large, markedly egg-shaped, and containing 

 numerous embryo colonies. 



On analysis, the water was found to contain -92 per cent, lime and 



