It meant that the nervous system of the ctenophore had evolved from the ground up, using a different set of molecules and genes than any other animal known on Earth. It was a classic case of convergence: the lineage of ctenophores had evolved a nervous system using whatever genetic starting materials were available. In a sense, it was an alien nervous system – evolved separately from the rest of the animal kingdom.
Source: What the ctenophore says about the evolution of intelligence | Aeon Essays
Lord Viking & Princess Wanda 