Title: The Crayfish of Allegheny County, Pa.
Description: This text explains the different species of crayfish found in North America and how they are classified into two genera depending on their location. The article also discusses the distribution of crayfish species worldwide and how their geographic patterns are linked to past geological events. Included is helpful information on identifying crayfish, such as their physical characteristics and details on specific species found in Allegheny County.
Subjects: Crayfish., Crayfish -- Anatomy.