:,:,«; 



Notes. 



B. Myonemes. 



After having looked in vain for illumination of the mvonemes 

 in Stentor, Spirostomwm, Dilcptus, and Vorticclla (probably too 

 small), we were able to detect a faint, but distinct, illumination in 

 the stalk of a large Carchesium. 



The immersion experiment failed to show any noteworthy 

 variation in the illumination, either for the sheath of the stalk or 

 for the contractile filament that it incloses. These elements must, 

 therefore, be considered birefringent, in contradiction to Rouget's 

 hypothesis, but in agreement with the opinion of Engelmann. 



C. Flagella of Spermatozoa. 



The faint, but yet distinct, illumination of the large sperma- 

 tozoa of Triton cristatus Laur. must be regarded as a phenomenon 

 of depolarisation. It is to be noted that the refractive index of 

 the liquid in which these organs become " extinguished " is a 

 little higher than that for the cilia : N L = 1-56 instead of 1 ■ 51. 

 This difference, which is quite evident, seems to be rather an im- 

 portant argument in favour of certain recent theories, which would 

 tend to separate these two elements from one another : — 



Xl 



33 

 36 

 47 

 49 

 51 

 54 

 1-56 

 1-58 

 1-60 

 1-66 



Liquid. 



Illumination. 



Water. 



Ethyl-alcohol. 



Glycerine. 



Castor-oil. 



Cedar-oil. 



Creasote. 

 I Various mixtures of 

 J creasote and bro- 

 mide of naphthaline 



J 



Bromide of naphthaline 



Distinct. 



Distinct, but fainter. 

 Very faint. 

 Very faint. 

 Practically nil. 

 Practically nil. 



Nil 



Nil ..... . 



Very faint, but distinct. 

 Distinct. 



Xl and X 



N L = N„ 



D. Swimming-plates of Ctenophora (Cydippe plumosa Chun.). 



The illumination here is also due to depolarisation. The ex- 

 tinction occurs in an index slightly higher; than that for ordinary 

 epithelial cilia : between 1ST L = 1*53 and 1 ■ 54 : — 



