Homarus americanus
Exercise from Invertebrate Anatomy OnLine covering the systematics, external and internal anatomy of the American lobster.
http://webs.lander.edu/rsfox/invertebrates/homarus.html

The Lobster Institute
A cooperative program of research and education with the lobster industry at the University of Maine. Information generated through the Institute about the American lobster (Homarus americanus) is intended to help conserve and enhance the resource, thereby ensuring the continuance of a strong and healthy industry in the state and the region.
http://www.lobsterinstitute.org/