Experiments showed that biarmed chromosomes of the mouse fibroblast L strain may possess 1, 2, or possibly 3 Cd-bands [variation of C-banding which reveals a dot-like body situated directly over location where the centromere should be]. If Cd-banding indeed stains centromeres, then the data suggest that chromosome fusions may result in biarmed chromosomes without the loss of a centromere, but such evidence is still circumstantial. Decisive proof should come from EM observations of these chromosomes to determine whether each of them has 2 kinetochores.