Ah, finally I found my watercolors and brushes!
The Meniribrachia are a (relative) new discovered phyllum of silvanian organisms. Most of them live in the endless dark of the abyssal plains but a few are also known from near the surface (but only very small species). These simple but rich in form lifeforms slide over the seabed and feed mostly on organic and anorganic particles and microbs, some of the bigger species, like the Mammoth Mentiribrachid, are also predators and consume much smaller relatives but also carrion.
green: digestion tract
blue: nerve system