That's kind of a bad joke.

I think reading about the Round Table Knights in British Literature class and studying about the evolution of vertebrates in AP Biology class at the same time isn't a bad idea.
The lancelet is a small, eyeless marine creature. It's considered the common ancestor of all vertebrates. Ask Ms. Wiki if you have questions about it.
Wikipedia:
[link]
That was a sudden inspiration.
I hope to draw more of those comics in the future.
Well, I don't know much about lancelet ecology. I only know Chinese people eat them.
The lanclet uses it more to feed himself, thats why another organ produces slime (mucus may be the better word) which´ll surround the gill slits and so will the muscus surround the incoming foodparticles and then it´ll digest it
The German word for gill slits is "Kiemendarm" this describes imao the function and very well, because it contains next to the word gill=Kiemen the word Darm
And because the way the lanclet feed himself is so expensive in energy (producing all the muscus) it is probably the reason for this creature of not growing bigger
hope i could help you in understanding
It's interesting that how lancelets actually use gills to forage food.