Nudibranch or snail hatching? Or something else?

[macnmotion]

Here is a compilation of several eggs I found in my salt water sample. At the 1:19 point, it certainly looks like the 2 coronas of a rotifer to me, but there are other parts that just don't look like any rotifer I've seen so far. Before I annotate the video I'd love to know exactly what it is.

Update: Someone has suggested this may be nudibranch veliger larvae. The larva would have 2 ciliated fins. It also appears it could be a small marine snail (see the very short second clip below).

The first scene is wide angle, with a 10X objective. After that it's shot with 40X oil, FOV is 360x200 microns.



Here is a very short clip that I've slowed down to 1/3X speed, it's all I could get in focus with the shallow DOF. I believe this is one after hatching, and we're seeing the internal membrane that is apparent in the longer video.

[Dennis]

macnmotion,

Priceless footage !
I would guess it is a rotifer.

[NachoBen]

Within the first seconds of the first video you can see (probably) a rotifer.

In the second video you can see a baby freshwater snail.

Congrats!

[macnmotion]

Within the first seconds of the first video you can see (probably) a rotifer.

In the second video you can see a baby freshwater snail.

Congrats!

This is salt water, not fresh, and the second video is just a few seconds of footage of the animals in the first video that I didn't include in that first video. Not a different animal.

I just took a look at the bamboo stick in my water sample and saw a tiny bullseye shaped pattern on the wood. I scraped it onto a slide, and struck the mother lode. Now I think I should try to move them into their own jar.