Scanning electron microscopy of Blastocystis hominis showed that its outer
coat has a fibrillar structure and individual fibrils may extend up to 5 mu
m from the periphery of the parasite. The surface coat remains intact duri
ng cell division. Bacteria are often seen adhering to it, but for the first
time a trophozoite of Chilomastix mesnili was also seen in this position.
It is postulated that breakdown of attached organisms may provide nutrients
for Blastocystis.