

"M 



B 



B 



Fig. 8. Electron micrograph (72 000 x ) of a thin section of a pellet of a pig- 

 mented fraction which sedimented previously as one component (50 S) in the 

 analytical ultracentrifuge. The preparation consists predominantly of small 

 particles with a diameter of about 150 A. There are also occasional elongated 

 figures (B) which are either contaminants or aggregates. 



