Abstract
Fabry-Perot interferometry was used to obtain the radial velocity field of M1-67, classified earlier as a planetary. The standard deviations of the velocities are in the range 40-70 km/s. With respect to the central star, the northern edge has excess negative velocity and the southern edge, excess positive velocity. This and the bi-symmetry of the structure suggest that the nebula is formed essentially by non-isotropic mass ejection from the central star by a mechanism proposed earlier for NGC 6164-5 and NGC 2359. The age of the nebula is estimated as 5800 years. Arguments are presented to conclude that M1-67 should be considered an H II region rather than a classical planetary nebula.
