Like a snail

Vermon Culp, Out Outdoor Neighbors,  Midwest Edition, 1949, p. 14.

They build these houses out of bits of sticks, leaves, or stones, and line them with Tough silk. These little dwellings always have a front door and back door…./…. The caddis worm doesn’t grow to his shell like a snail, but it holds fast to silk lining.