Seen under a microscope L. crystallinus very motile, about which later more.

The first photo provides a general impression of a Lophopus zooid. The polyp is clearly shown as is the upper part of the intestinal.
Through the microscope i could see the whip-hairs on the tentacles moving.

The second photo shows a better view of the internal part of a zooid. Both the mouth (inside the polyp) as the anus (to the left below the polyp) are clearly visible. The muscles that retract the polyp can be seen as elongated structures below the intestinal.
I did not realize that the surface of a Lophopus colony sac is dotted and not smooth before looking at Lophopus through a microscope.
I did not manage to capture the shine on the surface of the colon - unlike any other bryozoan i have seen.

In a detail cutout of the mouth are one can see the epistome as a 'roof' above the mouth. The esophagus can be seen as a vague structure inside a larger structure leading to the polyp.
It is typical bryozoan to have the anus end outside (underneath) the polyp, as can be clearly seen in this photo.
For extra ease of understanding i have added some labels to parts of the photo.

If the polyp is retracted, things become quite crowded.

Another view shows the polyp shape quite well. Also the retractor muscles are clearly shown.

This photo shows the muscles even better.

This animated series of photos shows how a colony moves. The photos are taken without changing anything to the microscope or the colony over a period of 2.5 minutes. Between the first and second photo is a longer pause then between the other photos. It took me a few seconds to decide to make a series.
Consequence of this amoeba like movement is that the zooids, that extend on the other side of the colony from where i was looking, are also continuously in motion.

Video through a microscope

The videos below are in WMV format and require a compatible player, such as windows media player, to view.
Each video is 30 to 60 seconds and 3 to 6 MB in size. Playing across a slow internet link may take a lot of time.

(click on the photo to start the video)

This video (6,5 MB!)shows normal behavior of a Lophopus zooid. Several times food is swallowed. Please note the movements of the epistome. Apparently the epistome has a more significant role than being a partial roof for the mouth, as is suggested in literature. Also can be seen how a polyp is moved abruptly to dislodge an unwanted object, in this case a strand of algae. Apologies of for the poor quality of the video. This was the first time i used a new microscope and more practice is clearly needed.

This video (3 MB) shows the effects of the colonies crawling movement on the zooids. Again apologies for the poor quality of the video.