Regents of the University of Michigan
Animal Diversity Web: Echinarachnius Parma (Sand Dollar)
Articles provieds information on the habitat, behaviors, and appearance of sand dollars, particulaly those that live off the coast of the northern United States.
Other
Wild Things: Seven Swinging Sand Dollar Facts
Written by a wildlife reporter for a newspaper, this blog entry about sand dollars briefly explains behavioral and feeding aspects of sand dollars on the west coast of the United States.
Monterey Bay Aquarium
Monterey Bay Aquarium: Sand Dollar
Article describes the natural history and some other "cool facts" about sand dollars, as well as some information on conservation concerns.