  We present deep, high-resolution imaging of the nearby Fanaroff-Riley Class I
(FR I) radio galaxies NGC 193, B2 0206+35, B2 0755+37 and M 84 at frequencies
of 4.9 and 1.4 GHz using new and archival multi-configuration observations from
the Very Large Array. In addition, we describe lower-resolution observations of
B2 0326+39 and a reanalysis of our published images of 3C 296. All of these
radio galaxies show twin jets and well-defined lobes or bridges of emission,
and we examine the common properties of this class of source. We show detailed
images of total intensity, brightness gradient, spectral index, degree of
polarization and projected magnetic-field direction. The jet bases are very
similar to those in tailed twin-jet sources and show the characteristics of
decelerating, relativistic flows. Except on one side of M 84, we find that the
jets can be traced at least as far as the ends of the lobes, where they often
form structures which we call "caps" with sharp outer brightness gradients.
Continuing, but less well collimated flows back into the lobes from the caps
can often be identified by their relatively flat spectral indices. The lobes in
these radio galaxies are similar in morphology, spectral-index distribution and
magnetic-field structure to those in more powerful (FR II) sources, but lack
hot-spots or other evidence for strong shocks at the ends of the jets. M 84 may
be an intermediate case between lobed and tailed sources, in which one jet does
not reach the end of its lobe, but disrupts to form a "bubble".
