Olympus 40/0.95, Canon 350D, DIC with electronic flash
Occasionally in "inner" space you come across a scenario that inevitably make you think of "outer" space. Such is the case with this large heliozoan, Actinosphaerium. This specimen measured about 500 micron (0.5mm) in diameter, which makes it a pretty large member of the protist family. When observing it through the microscope, it's hard not to imagine a celestial body floating through space, or perhaps the sci-fi "mother ship". There is all sorts of activity going on at different levels. The cytoplasm regularly flows up and down the axonomes. Many smaller protist can be found around the surface (and if they are not careful, some will join others inside as a meal).
The first image (above) shows about 1/4 of the heliozoans "body", with a Synura colony moving about through the axonomes.
The second image (below) shows an overall view. You can see the very characteristic layer of large vacuoles at the outer edge of the cell.
Olympus 10X, Canon 350D, DIC with electronic flash
While I watched and photographed this heliozoan, I regularly observed rotifers (Keratella) approach and with their cilia, scour the axonomes for food. This activity is seen below.
Olympus 40/0.95, Canon 350D, DIC with electronic flash
)