[Presence of abundant heterochromatin in the karyotype of Cebus: C. cappucinus and C. nigrivittatus]. / Présence d'une hétérochromatine abondante dans le caryotype de deux Cebus: C. capucinus et C. nigrivittatus.

The karyotypes of Cebus capucinus and C. nigrivittatus (Primates, Platyrrhini) are compared after applying several banding techniques. The chromosomes have abundant intercallary heterochromatin which can be stained by R-, T- and C-band techniques and which are late replicating. The X chromosome resembles that of man and of numerous primates. However, the late replicating pattern of the X in female lymphocytes resembles that of the late replicating X of human fibroblasts rather than of human lymphocytes. Banding patterns of certain chromosomes appear analogous in Cebus and Cattarhini, including Man.