Answer
A colonial bryozoan.
Reader Judy Brook found and photographed this 10-inch bryozoan in Church Pond in the Adirondacks. Pectinatella magnifica is a member of the animal phylum Ectoprocta (common names: bryozoans, moss animals), a group with a fossil record extending back 500,000,000 years.
This week’s contest winner was Edith Sisson of Concord, MA