Observations on Euglena deses. 
BY 
ROSE BRACHER. 
With nine Figures in the Text. 
Contents. 
PAGE 
Section I. Introduction 93 
„ II. Daily Movements of E . deses dependent on External Factors , 95 
„ III. Behaviour of E . deses when removed from the Influence of the 
Tide 99 
,, IV. Further Investigations of the Influence of Light and Temperature 
on the Behaviour of E. deses 100 
,, V. Depth to which E. deses burrows in Mud 104 
„ VI. Climatic Conditions 105 
„ VII. The Need for Oxygen 106 
„ VIII. Summary 106 
„ IX. Conclusion 107 
Bibliography 108 
Introduction. 
T HE organism with which this paper has to deal occurs along the banks 
of the river Avon within its tidal portion, which extends for about 
seven and a half miles inland. The actual point at which the present work 
was for the most part carried out is about a quarter of a mile lower down 
the river than the Clifton Suspension Bridge. At low tide the river in this 
part of its course is reduced to a very narrow stream, leaving exposed on 
either side wide stretches of mud. 
On examining the surface of the mud, one can see that parts are 
coloured bright green, while in other places the mud appears yellowish 
brown in hue. Closer examination reveals the fact that the green colour is 
restricted to small patches varying from a quarter of an inch to one inch in 
diameter, and often so close together as to form an almost continuous 
carpet. 
[Annals of Botany, Vol. XXXIII. No. CXXIX. January, 1919.] 
