  We have re-analyzed the ultraviolet spectrum of HD 44179, the central star(s)
of the Red Rectangle nebula, providing improved estimates of the column
density, rotational, and vibrational temperatures of the 4th Positive A-X
system of CO in absorption. The flux shortward of 2200 A is a complex blend of
CO features with no discernible stellar photosphere, making the identification
of other molecular species difficult, and the direct derivation of the dust
extinction curve impossible. We confirm that the spin-forbidden CO (a-X)
Cameron bands are likely produced by either collisional excitation or a
chemical reaction, not photoexcitation, but with a higher internal vibrational
excitation than previously determined. We also detect the spin-forbidden CO
a'-X, d-X, and e-X absorption features. The hot CO (A-X) bands exhibit a
blue-shift of ~300 km/s, likely occurring close to the white dwarf star(s)
suspected as the original source of the ultraviolet flux in the system, and
forming the base of the outflow of material in the Red Rectangle. The OH
"comet-band" system near 3000 A is also analyzed, and estimates of its
rovibrational temperatures determined. The source of the molecules studied in
this system is still unknown, but may be a combination of gaseous material
associated with the star(s), or processed material from the surrounding dust
torus.
