Aorotrema cistronium (Dall, 1889a) Three-keel Vitrinella Scanning Electron Micrographs

    Lower Pinecrest beds, Upper Tamiami Formation, Sarasota County, Florida (1.32 mm. on the top and 0.63 mm. juvenile on the bottom). SEMs produced in collaboration with Dr. Ann Heatherington, Dept. Geological Sciences, University of Florida, Gainesville, FL.