抄録
Skeletal variation, Seventh cervical vertebra, Foramen transversarium, Heredity, Mouse Summary: The formation of foramina tansversaria in the seventh cervical vertebra of CBA and C57BL mice and their offspring is found to behave as if it is determined by a single semi-dominant gene. The accessory foramina of Weber (1950) are investigated in the same material. These foramina are classified into two types and their heredity is evaluated.