STUDY OF PELOMTXA PALUSTEIS. 385 



used created a crinkled and unnatural condition of the filaments. 

 The filaments in the other flasks, which contained older cultures, 

 had, on my return, already broken down to form short rods, so 

 tliat the cycle had been completed without my being able to 

 state at exactly what period this breaking-down had taken place. 

 It will be seen, however, that the stages observed in (1) the fresh 

 condition, (2) in cultures, were five in each, and that, as the 

 following table shows, the stages in (1) were exactly parallel and 

 similar to those in (2) and may fairly be considered identical. 



Fresh Preparations. Cultures. 



Stage 1. Motile 2-jointed rods (units). 1. Motile 2-jointed rods. 



„ 2. Fixing of unit on refring-ent 2. Fixing on solid bodies. 



bodies. 



,, 3. Growth to form long filaments. 3. Growthto form filaments. 



„ 4. Pseudo-branching of filaments. 4. Pseudo-branching of 



filaments. 



„ 5. Breaking-down to form short 5. Breaking-down into short 

 rods. rods. 



Although the circumstances of this case necessitated a mode 

 of procedure necessarily less exact than that justly demanded in 

 most bacteriological experiments, yet the above stages which 

 have been observed and recorded form a complete cycle of 

 development ; and the conclusion reached must surely be, that the 

 life-history of the bacteria characteristic of Pelomyxa has been 

 placed beyond reasonable doubt. 



Identification of the Sacteria. 



The classification follow^ed is that of Migula. The order is 

 that of Eubacteria. From the character of the sheathed filament, 

 and the reproduction by " swarmers " set free and immediately 

 recommencing the cycle, the bacteria of Peloviyxa belong to the 

 family Chlamydobacteriacese. 



Erom the single contour of the walls of the sheath, from the 

 equal size of the filament from base to tip, and from the pseudo- 

 dichotomous branching, the bacteria belong to the genus 

 GladotJirix, Oo\\n=^ Sphcerotilus (Kiitzing, Mig.). Only two 

 species of this genus are known — viz., Sphcerotilus dicJiotomus 

 (C. dichotoma, Cohn), and Sphcerotilus natans, Kiitzing. The 

 species in question differs from both in one important particular, 

 viz. — the free rods or swarmers of Pelomyxa are straight and 

 always most distinctly and sharply truncated at the ends. 



