I have studied the galactic longitude distribution of low latitude pulsars on the assumption that pulsars are evenly distributed in the galactic disk but that their observability is severely impaired by spiral features, rich in H II regions, in which the high electron density causes a high dispersion measure for a comparatively short optical path. The assumption of even distribution in the galactic disk seems natural as no correlation between positions of pulsars and spiral tracers is known, and since supernovae in external galaxies are not known to confine to spiral arms.