sentences:  Galiana takes Felka away, and Clavain and Iverson talk.Clavain has realised by now that "Iverson" is actually Setterholm, who killed the real Iverson and swapped the records of their identities.Setterholm had discovered that the worms and the tunnels they dug through the ice (which were coated in chemicals which determined which way the worms went down them, much like a human brain) had become a massive natural information processor, which he believed either was or was becoming a sentient mind.