GENERAL CHARACTERS OF SPIROOELETES. 17 



Sp. anodonta, which are easily obtainable, as well as, to 

 a less extent, in the typical species Sp. plicatilis. De- 



FIG. i. FIG. 2. FIG. 3. 



FIG. i. Spirochaeta plicatilis : Schematic. (After Doflein.) 

 PIG. 2. Spirochaeta balbianii, showing so-called "undulating 



membrane." (Perrin.) 



FIG. 3. Spirochaeta anodontae, with "undulating membrane." 



(Keysselitz.) 



scribed in general terms, they are elongated, vermi- 

 form organisms, endowed with active movement. They 

 are said to be flattened from above downward, thus 



