A selfplex is a number of meme
s that inhabit the same physical shelter, i.e. somebody's brain. Its function is to protect and help propagate its memes, that will likely have co-adapted in order to share the same selfplex.
A selfplex is a different thing from a memeplex, i.e. a system of belief made of many memes that have evolved in order to work together; because it's known that memes replicate better in pools.
Both concepts were coined by dr. Susan Blackmore in her The Meme Machine book and following work.
I am a selfplex. You are, too. This memetics is viral.