Today I would like to introduce Askenasia volvox, an egg-shaped ciliate belonging to the family Didiniidae, which I found in a puddle. His mouth is surrounded by three girdles of cilia. The frontal girdle consists of motile feeding cilia. The middle girdle consists of about 60 stiff, immobile, sickle-shaped cilia, which are curving backwards, parallel to the body. These middle cilia produce the saltatory locomotion typical of this ciliate. Behind the middle girdle of cilia follows a girdle of long stiff bristles. The posterior end of the cell is unciliated. When looking along the longitudinal axis, which is possible during the frequent rest periods of this otherwise very fast swimmer, the middle girdle of cilia forms a graceful frame surrounding the animal. The long stiff bristles, which are diffucult to discern under rightfield illumination, then project through the middle cilia. Depending on the focal plane and whether the front or back end of the ciliate is directed towards the observer, very different views result.
A: Lateral view; B, C: Frontal view; D – F: View from behind.
All photographs were taken with a Canon Powershot G5 camera through a Plan-Neofluar 40x/0,75 objective attached to a Zeiss Axioskop, using brightfield illumination.
Bernd
). Charlie, a few days back suggested that a scale bar would be nice to have in one of my images, figuring out anything having to do with numbers has me screaming, waving my hands and heading for the door, sort of like tying size 32 midges, so without me having to breakout a sliderule or something, could you explain how you know that little line represents 10um in relation to the organism photographed and presented? I mean could someone say just...put any line in that corner, no matter how short or how long and say it represents 10um's? I would not know the difference one way or another. In laymans terms explain please. 
