464 MR. HAROLD WAGER ON THE 



' Traite de Zoologie Concrete ' by Yves Delage and Edgard 

 Herouard *. 



A memoir by Kliawkine t also contains valuable information 

 on the structure and physiology of Euglena viridis. For further 

 information concerniog the numerous memoirs in which the 

 structure of Euglena is dealt with, the reader is referred to the 

 papers quoted above, which contain complete bibliographical lists 

 of the literature on the subject. 



Without attempting to give a complete account of the structure 

 of Euglena viridis, it may be useful to briefly summarize what is 

 contained on the subject in the memoirs already published, 

 which my own observations enable me to confirm. 



In the free swimming condition, the animal is elongate and 

 cylindrical in shape, slightly larger in the middle than at the 

 ends ; the anterior end being truncated, the posterior usually 

 pointed. It is a unicellular organism, jDrotected on the outside 

 by a thin skin or layer of modified protoplasm which is striated 

 obliquely by slightly elevated ridges. These can be made visible 

 by crushing the cell and squeezing out the protoplasmic contents 

 under a cover-glass. Under certain conditions, of which one 

 appears to be malnutrition, I find tliat the cells, while still 

 retaining their power of movement, become curiously distorted 

 and deformed, and might easily be mistaken for distinct species. 

 This apparently accompanies a process of slow disintegration. 



The protoplasm contains numerous chlorophyll-bodies, some- 

 times scattered all over the cell, with the exception of a short 

 space at the anterior end which always remains colourless, but 

 more often radiating from the centre, leaving both anterior and 

 posterior ends free. In many cases, especially in cells freshly 

 collected, it is not easy to distinguish the separate chlorophyll- 

 bodies ; and this led Saville Kent {loc. cit.) to regard the chloro- 

 phyll as diffused through the protoplasm ; but it is only necessary 

 to keep such cells in obscurity for a short time, in ordinary tap- 

 water, or to examine them under a high power of the microscope, 

 to see that the chlorophyll-bodies are really definite organs of 

 the cell +. 



* Vol. I. La Cellule et les Protozoaires. Paris, 1896. 



t " E.echerches biologiques sur Y Astasia ocellaia n. s. et VEuglena viridis." 

 Ann, des Sci. Nat. 7th series, vol. i., 1886. 



X Klebs, I. c. p. 264. See also Jessie A. Sallitt, " On the Chlorophyll 

 Corpuscles of some Infusoria," Q. J. M. S. 1884. 



