PLATE I. 



Taken from " Monthly Microscopical Journal," of Sept. 1st, 1875. 



FIG 1. a. B. termo magnified with the same power as b, which 

 is a specimen of Spirillum volutans, showing flagella at each end. 



FIG. 2. B. termo, as seen with a power of about 600 diameters. 



FIG. 3. The same as seen with -^ and second eye-piece (3,700 

 diameters). 



FIG. 4. B. termo, seen with flagellum at one end, the light com- 

 ing in the direction of the arrow. 



FIG. 5. The same object when it moved at right angles to its 

 former position, the light coming from the same direction, causing 

 the sight of the flagellum to be lost. 



FIG. 6 represents one B. termo which was in a still condition, 

 but one flagellum moving. The light came in the direction of the 

 arrow. When the end marked 2 b was in focus, a flagellum was 

 seen, but none at the end c. When the end marked 1 a was fo- 

 cused carefully, the flagellum at that end was seen, and lost at the 

 end d. 



FIG. 7. The true form of B. termo. 



FIG. 8. The form as shown by the " supplementary stage " il- 

 lumination before flagella were found, showing the pointed ter- 

 mination of the body at a, b. 



