99 



AUSTRALIAN FRESHWATER FLAGELLATES. 



By G. I. Playfair. 



(Plates i. to ix.; and three Text-figures.) 



In the present paper I have endeavoured to give some account of all those 

 forms of microscopic life found in our waters, which are included under the 

 class Fhigellatae of the freshwater Algae. From the early days of my studies 

 I have always felt a lively interest in the freshwater flagellates and looked for- 

 ward to a time when I should be in a position to set forth some small attempt 

 at a monograph 'f such as occur locally. The following notes therefore, dealing 

 with almost a), the commonly occurring species and with a large number of 

 forms, also, w'lieh are not at all common, represent the gleanings of 15 years. 



The moi'e important part of the work, however, was accomplished during 

 the period .en, as a science research scholar of the University of Sydney, I 

 was enabled to devote myself for some years to a more thorough investigation of 

 Australian pond life than 1 had previously dune. It is with pleasure, therefore, 

 that I here express my heartiest gratitude to the Senate of the University for 

 afforded me the opportunities which have resulted in my bringing a long- 

 cherished desire to a successful issue. 



In conjunction with these notes should be taken my earlier paper on "The 

 Genus Trachelomonas.'' (These Proceedings, xl., 1915) which was written in 

 advance, on account of the verj' large number of new forms observed in that 

 genus. The title "Australian Flagellates" may perhaps be considered too grand 

 when it is obser\'ed that all the gathering's were made in two localities only, viz. : 

 — the suburbs of Sydney and the neighbourhood of Lismore. This, however, is 

 not so, for the Flagellates are entirely cosmopolitan and the ordinary forms 

 always very wide-spread. In moving from one district to another one merely 

 picks up the same common form ov«r and over again. The rarer varieties, on 

 the other hand, are generally polymorpliic forms without any local attachment 

 whatever, but merely the result of unusual combinations of rain and shine, tem- 

 perature, movement and stagnation in their habitat. It is for tliis reason that 

 they are uncommon. They are entirely the product of their environment. In a 

 very large number of cases also, they are simply stages of growth which have 

 become fixed at that point either by the induration of the cell-wall or by the 

 lack of any stimulus to further growth. 



