George Migaki,¹ RICHARD A. HECKMANN,² THOMAS F. ALBERT<sup>3

1</sup>Registry of Comparative Pathology, Armed Forces Institute of Pathology, Washington, D.C. 20306, USA
²Department of Zoology, Brigham Young University, Provo, Utah 84602, USA
³Department of Veterinary Science, University of Maryland, College Park, Maryland 20742, USA