Photo By/Credit
Simanek, Kristin/USFWS
Media Usage Rights/License
Public Domain
Image
The three primary types of glochidia in the North American Unionidae. Subtriangular, hooked glochidia (left), axe-head glochidia (center), and semi-elliptical, hookless glochidia (right). Graphic: Kristin Simanek, USFWS.