J^J^'l Field Naturalists' Club — Proceedings. 53 



On the motion ot Messrs. Strickland and Gates, a hearty 

 vote of thanks was accorded to the retiring office-bearers. 



PAPERS READ. 



I. By Mr. A D. Hardy, F.L.S., entitled "The Alg« of 

 the Flamingo Pool, Zoological Gardens, Melbourne." 



The author remarked that the Melbourne Zool'ogical Gar- 

 dens contain several pools of water supplied from the Yan 

 Yean and Maroondah systems, but special attention was 

 drawn to the pool in the Flamingo enclosure, the water of 

 W'hich is coloured grass-green for the greater part of the 

 year. Microscopical examination disclosed the fact that this 

 colour is due to microscopic plants of a few species but in 

 prodigious numbers. Some of the species are cosmopolitan, 

 and may be found in the Yan Yean, but others are compara- 

 tively rare, particularly one, which has hitherto been found 

 only in Burmah. Sometimes one species dominates the 

 pool, but later another will attain pre-eminence, and 

 again, at a later stage, these may be absent or rare in 

 the presence of a totally different plant. Towards midwinter, 

 how^ever, the microflora decreases rapidly and animal organ- 

 isms increase in inverse proportion. The paper was illus- 

 trated by means of blackboard diagrams. 



Prof. Ewart said it was evident that the author had been 

 making some interesting observations. He thought that the 

 Zoological Gardens would be a good place to find micro- 

 scopical objects of great interest. These might be carried 

 there by air current or upon animals imported from other 

 countries. A specially interesting fact was the succession of 

 life in pools which has alw.ays been a difficult problem to 

 solve. One suggestion put forward was that one set of 

 organisms poisoned the water so that forms inhabiting the 

 medium subsequently could not live for any length of time 

 in it. just as it was thought that one crop poisoned the ground 

 for another. As a matter of fact there was no evidence in 

 support of the theory, as has been shown by chemical 

 analysis. A probable factor was temperature. Several 

 algae have well-defined temperature limits, and can only 

 grow^ at their best at one particular temperature. Change of 

 temperature affects the supply of oxygen and carbon dioxide, 

 and this in turn affects the food supply of the algae, hence 

 the predominance or absence of certain forms at different 

 periods. 



Mr. J. Stickland said he had seen some of the species in 

 other localities, and had also observed the now newly re- 

 corded Euglena. 



Mr. J. Searle mentioned that he had found two of the 

 common species mentioned by the author in Lake Catani, 

 Buffalo Mountains. 



