On the oyster’s edge, under the sea, on a rock, a tree root, a bamboo pole, a pebble, a tile or another shell, the bivalve’s cilia – from the Latin for eyelash – are waving. Together, they move water over the oyster’s gills – its shell is open, its muscles are relaxed. The oyster has lungs. It has a three-chambered heart. An hour passes; the oyster has filtered five litres of water. The oyster has listened to the breaking waves: it opens and closes according to the tides.
One valve is the cupped half of the shell, the other is the flat half. A cargo ship sounds its horn. The oyster shuts in fright.
Above the water, in Lewis Carroll’s Through the Looking Glass, the Walrus and the Carpenter are “walking close at hand”. The sun is shining in the middle of the night. The moon has opinions about this. (In the Disney cartoon, the sinister Walrus and the Carpenter stroll between two halves of a screen: one light, one dark. The Walrus spins his cane).