BTUDIES 



ON THE OCCURRENCE AND REPRODUCTION 



OF 



British Freshwater Alpe in Nature 



3. A four years' observation of a freshwater pond 



F. E. FRITSCH, D. Sa, Pu. D., F. L. S. 



Professor of Botany, East London Collège, University of London 



Florence RICH, M. A., 



(Somerville Collège, Oxford; Granville School, Leicester). 



(1) 



TABLE OF CONTENTS 



A. General considération ofthe physical leatures of the pond and ofthe 



meteorological data 35 



B. The flora ofBarton's pond 39 



C. The animal cycle 45 



D. Considération ofthe periodicity of certain forms 50 



(a) Zygnemaceae (p. 50). (g) The Protococcales (p. 73). 



The Desmids (p. 55). (// ) The ( yanophyceae (p. 81 ). 



(c) The Oedogoniaceae (p. 58). (/) The Flagellâtes (p. 82). 



(d) Thegenns Microspora (p. 62). (j) Peridiniwm (p. 86). 



(e) The Confervales (]i. 68). (/;) The Diatoms (p. 87). 



ilie genus Chaetopkora (p. 71). 



/;' General considération of the periodicity-data ofthepreceding section U2 



F. General considération of reproduction in Barton's pond. .... 99 



itematic notes 106 



H. Summary lit'.' 



Bibliography 113 



(!) The first paper of this séries was published in Armais of Botany, vol. 

 XXI, July, 1907, pp. 423-36; the second in the Bristol Naturalists 1 Society' 's 

 dings. 4fi* ser., vol. II, part, II. I909(issued for 1908). 



3 



