I track the #Volvox hashtag on Twitter, which is how I find out about a lot of the off-label uses of the name Volvox, like DJ Volvox, Volvox the ship, and Volvox the art gallery. Every now and then, it even turns up something related to Volvox the little rolling algae. The other day, @QuintaSwinger tweeted the following video with #Volvox:

The Twitter handle is about just what you think it is; apparently volvocine sex puts someone in mind of polyamory. I suppose I can see that: when a sperm packet enters a colony, it gets busy with all the ova. The video was uploaded to YouTube by Dr. Donald Ott from the University of Akron.

I think the algae in the video are not actually Volvox, though. Certainly the still photo at the beginning is Volvox. Probably not section Volvox (too few cells), and probably not Developmental Program 2 (germ cells too small in the one on the lower right). If I had to guess, I’d say V. aureus, but that’s largely a Bayesian bet because they’re so common. Maybe Alexey Desnitskiy or Hisayoshi Nozaki can comment.

The colonies in the video, though, look more like Pleodorina to me. Not P. sphaerica, since the somatic cells are all in the front, but without more information I can’t narrow it down more than that.