Pseudofeces

Pseudofeces or pseudofaeces are a way that filter-feeding bivalve mollusks (and filter-feeding gastropod mollusks) get rid of suspended particles which have been rejected as unsuitable for food. The rejected particles are wrapped in mucus, and are expelled without having passed through the digestive tract. Thus although they may closely resemble the mollusk's real feces they are not actually feces, hence the name pseudofeces, meaning false feces.