Skin biopsies of two male and two female animals were kindly provided by Dr. J. K. Frenkel, University of Kansas, Kansas City, Kansas, USA. These animals were identified by Dr. J. Knox Jones, University of Kansas Museum of Natural History. All chromosomes possess distinct short arms. The Y chromosome shown here is almost acrocentric, but it also often displays a short second arm. It is late replicating. The X was identified by autoradiography. This karyotype differs from M. auratus (Folio 14) but is similar to that of the Kurdistan hamster described by Lehman and MacPherson. It is also identical to that presented by Ivanov.