no idea... (a picture added)

Franz Neidl · Post by **Franz Neidl** » Sun Feb 05, 2012 5:06 am

It is from marine plankton. The diameter was 220 µm. What could it be?
Objective 20x, DIC.

Franz

Greg Gavelis · Post by **Greg Gavelis** » Mon Feb 06, 2012 9:16 am

Dear Franz,

Judging from the tiny cells on the outside, that may be the egg of an ascidian. Sea squirts usually have "test cells" accompanying the egg, which secrete a covering on the larva as it develops. Here are some timelapse videos of test cells and ascidian development. Different species, of course.

http://celldynamics.org/celldynamics/ga ... lla02.html

http://celldynamics.org/celldynamics/ga ... tenia.html

Franz Neidl · Post by **Franz Neidl** » Sun Feb 12, 2012 3:16 am

Hello Greg,

thank you for your precious help. I agree with you and add an additional picture which I made from an Ascidian larva. But I have to admit that up to now I do not know what are "test cells". Marine life sometimes seems me a little bit complicated... But I will inform me.

Franz