  (Abridged) We present results for J and Ks near-IR imaging data on a large
sample of 88 galaxies drawn from the catalogue of Impey et al. (1996). The
near-IR data unveils many features of LSBGs not seen before in the optical.
First, a high fraction of the observed LSBGs are very luminous in the near-IR,
indicating that they have a well developed old stellar population, and that
older LSBGs are more frequent in the universe than data from optical bands
suggested. Second, the near-IR morphologies are often quite different than seen
in the optical. Third, we find significant trends between the near-IR
morphologies of the galaxies and their ratio of HI mass to near-IR luminosity.
Fourth, we find no trend in disk surface brightness with absolute magnitude,
but significant correlations when the bulge surface brightness is used.
Finally, we find that the formation of a bulge requires a galaxy to have a
total baryonic mass above ~ 10**10 Msun. A wide variety of other correlations
are explored for the sample. The strongest of our correlations are with the
ratio of HI mass to total baryonic mass, MHI/Mbaryonic, which tracks the
evolutionary state of the galaxies as they convert gas into stars, and which
ranges from 0.05 up to nearly 1 for the galaxies in our sample. We see also
trends between MHI/Mbaryonic and central surface density, suggesting that
increased star formation efficiency with increasing gas surface density
strongly drives the conversion of gas into stars.
