Peripheral blood smears from 7-day-old hea and fsn mice show several disturbances in red cell morphology. Marked anisocytosis, polychromasia, poikilocytosis, nucleated red cells, naked nuclei, and smudge cells are observed in hea and fsn pup blood smears as compared with a normal pup littermate. Micrographs were prepared using an Olympus VANOXT AH2 Version microscope and an Olympus camera (both from Olympus, Melville, NY). High dry objective lenses with a numerical aperture of 1.25 and an objective of 60× at a magnification of 600× were used. The images were scanned and labeled with Adobe Photoshop software.