pink rice-grains, ink- bespattered jelly fish, crabs like green lilies, and submarine toadstools, slide each on the other.
So we're back to the pretty language again. Here again, Moore is dissolving one setting into another pretty smoothly by connecting the last idea of one stanza into the first idea of the next.
So, it looked like we were headed into the sky at the end of the last stanza with the mention of stars, but we might have been given the slip with some poetic misdirection. Sure, stars may look like "pink/ rice-grains" if you squint at them long enough, but we doubt that you'd see anything in the sky that resembled "ink-/bespattered jellyfish." Storm clouds maybe? Alien ships that have come to invade earth? Those are both possible (we welcome you, new alien overlords), but another possibility is that this poem has zigged when we thought it zagged.
Don't forget that we've been or near the sea so far. So what kind of star might live as easily under the water in the sky? Yup, starfish might—and pink ones at that. So here we might actually be back under the sea, chockfull of figuratively depicted starfish ("stars, pink rice-grains"), jelly fish, and crabs among others. And they're all getting along rather nicely in a connected sort of way, "slid[ing] each on the other."
So not only do we have a change in scenery (from sea to cliff to sky—er, nope, back to sea), but also a change of mood. We ended the previous stanza on a rather violent note and here things are looking pretty peaceful, even ready for a cameo in The Little Mermaid.
To heighten the peace, everyone getting along kind of mood, the speaker lists off all the different creatures in a highly vivid way, one after another. Again, this is not totally dissimilar to the kind of song you'd hear in a Disney movie.
And each description is a figurative whirlwind of images, from "rice-grains" (like the spots on the starfish) to "ink-bespattered" jelly fish (probably dark or splotchy). The "submarine toadstools" might be another wartime allusion to the violence and death that is always a part of life.
Notice too that, with this new setting, we're kind of moving in circles since we started in the ocean, moved to land, and now we're back in the ocean. So, even the changes of scenery mimic the undulating movement of the ocean's waves as we go back and forth.
Oh, and we ended this stanza with a period, which is a bit different from all the enjambment we've seen so far. This tells us that this particular thought has come to a full stop and perhaps the next stanza will therefore focus on something different. Only one way to find out…