Italian tax police said Saturday that they had seized works by Van Gogh, Picasso, Cezanne and other giants of art in a crackdown on assets hidden by the disgraced founder of the collapsed dairy company Parmalat. Authorities estimated the 19 masterpieces stashed away in attics and basements were valued at some $150 million. Parma Prosecutor Gerardo Laguardia said that, based on wiretapped phone conversations, officials believed at least one of the paintings hidden by Calisto Tanzi was about to be sold. Among the masterpieces was a pencil on paper portrait of a ballerina by Degas, two Van Goghs, including a depiction of a trunk of a willow tree and a still life, a watercolor by Cezanne and a pencil-work by Modigliani. Tax police official Massimo said some of the paintings were carefully wrapped for protection, but that other paintings, including a Picasso, were left open in the store room.