A detailed karyotype comparison amongR. cornutus cornutus, R. ferrumequinum nipponandR. luctus formosaeare made on the basis of relative length, G- and C-band patterns. The data presented here suggest strongly M.SM-1 and 2 inR. f. nipponwere formed by centric fusion of four of five small A-autosome pairs such as those in A-23∼25, 27 and 28 ofR. c. cornutus, while occurrence of M-SM-3 in the former was caused by pericentric inversion of a small A-pair such as that in A-24 or 25 of the latter, confirming the assumption described in our previous report (ANDŌet al.1980a). On the other hand, appearance of the secondary short arms of A-autosomes inR. f. nipponis attributable to the C-band material added to the telomeres of A-autosomes. Addition of heterochromatin is considered to have taken place also in the short arm of the ST-X chromosome inR. f. nippon, and to have brought about the morphological difference of the Y chromosome withinRinolophus.