Posell, Elsa Z. The beginning knowledge book of seashells / Seashells by Elsa Z. Posell. Illustrated by Raul Mina Mora. - [New York : Rutledge, 1969. - 35 p. : ill. - Beginning knowledge books . The five groups making up the mollusks. LCCN: 68010733 Subjects--Topical Terms: Shells. Dewey Class. No.: 594