A slug is a land snail without a shell,"" says Pollock's appended note. From this fact she has made a small story about a slug who lets a snail convince him that he (the slug) is simply a snail who has lost his house. The snail takes him off on a search for a new shell, and leads him into all sorts of situations that are okay for snails but uncomfortable for the shell-less kind. Then an accidental meeting with another slug sets the deluded one straight. It's a painless way for kids to soak up a basic fact or two about slugs and snails, but otherwise unengaging--as are Cauley's puffy-fat, pink-cheeked characters.